Sentry vs Stratus (2026): Which ADS-B Receiver Should You Buy?

Last updated: June 22, 2026. By Neil Glazer, Pilot Mall staff pilot.

Pilot Mall is an authorized Appareo dealer, we stock the Stratus 4, and we also carry the Garmin GDL 50. We do not sell ForeFlight's Sentry line; we include it here purely as a comparison benchmark so you can see exactly how the receivers we carry stack up against it. Where the Sentry genuinely leads on a single spec, we say so plainly, and then we explain why the Stratus 4 (or, for Garmin pilots, the GDL 50) is still the better receiver to actually own.

Specs and prices below were verified against current retail listings and our live catalog, including the fact that the Stratus 3 is discontinued, which most comparison articles still miss. Where pilots on owner forums raised real-world concerns, we address them directly rather than reprinting spec sheets. Where a spec couldn't be publicly verified, we say so instead of guessing.

The 30-Second Verdict

The Receivers We Stock

Below are the portable ADS-B receivers we actually carry and can ship to you. (The ForeFlight Sentry line is named throughout for comparison only, but we don't sell it, see the note above.)

Appareo Stratus 4 ADS-B Receiver

$849.00 · In stock

• Open GDL90, works with ForeFlight, Garmin Pilot, FlyQ, WingX & more, iOS and Android
• Full-color touchscreen; user-replaceable battery (~8 hr); Apple Find My
• Dual-band ADS-B, subscription-free FIS-B weather, WAAS GPS + AHRS

View the Stratus 4 →

Garmin GDL 50 Portable ADS-B Receiver

$850.00 · In stock

• The Garmin-ecosystem alternative if you fly Garmin Pilot or aera/G3X portables
• Dual-band ADS-B (978 UAT + 1090 ES); subscription-free FIS-B weather; WAAS GPS + backup attitude
• Streams to ForeFlight, Garmin Pilot & FltPlan Go over Garmin Connext; ~8 hr battery

View the Garmin GDL 50 →

Want to see the full lineup? Browse our portable ADS-B receivers & subscription-free weather collection.

Why This Comparison Is Harder to Research Than It Should Be

The answers out there are forum threads from 2021, Facebook posts you can't read without logging in, and ForeFlight's own chart that only compares its own devices. Two market facts changed in 2025/26 that most pages still miss: (1) the Stratus 3 is discontinued, out of stock at Appareo and replaced by the Stratus 4 at $849, and (2) Sentry pricing settled at roughly Mini $399 / Sentry $599 / Plus $799. This is the Sentry vs Stratus comparison built on current facts, for the ForeFlight Sentry and Stratus ADS-B buyer who wants the truth, not a stale chart.

The 4-Way Comparison Table (Current Models Only)

This is the only table comparing the four models you can actually buy new in 2026, Sentry Mini, Sentry, Sentry Plus, and Stratus 4. The Stratus 3 is omitted because it's discontinued (see below). Of these, only the Stratus 4 is sold at Pilot Mall; the three Sentry models appear here strictly as comparison benchmarks.

App Lock-In: The Decision That Actually Matters

Sentry (all three models) is ForeFlight only, iOS only. ForeFlight does not run on Android, and the Sentry will not output GDL90 to other apps. Buy a Sentry and you've committed a $399 to $799 receiver to one app on one operating system.

Stratus 4 uses open GDL90. It works with ForeFlight, Garmin Pilot, FlyQ EFB, WingX, FltPlan Go, and Appareo's own Stratus Insight, on iOS and Android. (Historical irony: Stratus began as the ForeFlight-exclusive receiver; the roles have fully reversed.)

What happens if you switch EFB apps later?

ForeFlight subscriptions run roughly $120 to $250+/yr. If Garmin Pilot or a future app tempts you in year two, a Sentry owner must also re-buy hardware (about $600 to $800), while a Stratus 4 owner just pairs the new app. Renters and CFIs flying with students on different apps feel this immediately. (Committed to the Garmin ecosystem instead? The Garmin GDL 50 is the natural fit there, and we stock it too.)

In fairness: inside ForeFlight, the Sentry integration is genuinely deeper, CO alerts, FLARM display (Plus), tracklog auto-import, and device settings all live natively in the app. But that depth is the trap, not the prize: it ties an $800 piece of hardware to a single app and a single OS, and you pay for it again the day you switch. The Stratus 4 hands you the same dual-band traffic and subscription-free weather inside ForeFlight today, and keeps working if you ever move to Garmin Pilot or Android, which is exactly why it's the smarter buy even for today's ForeFlight pilot. One nuance competitors miss: the Stratus 4's AHRS drives synthetic vision/attitude in ForeFlight and other GDL90 apps that consume AHRS, but support varies by app, confirm your specific EFB consumes Stratus AHRS before buying for that feature.

Feature-by-Feature Breakdown

ADS-B reception & traffic

All four are dual-band (978 UAT + 1090ES) with subscription-free FIS-B weather. Don't let anyone upsell on "better ADS-B", reception is a wash, so it can't justify locking yourself to one app. The one differentiator: FLARM display is Sentry Plus only (glider/European traffic, niche but unique). For the handful of pilots who truly need FLARM that's a real edge; for everyone else the Stratus 4 delivers identical core traffic without the lock-in.

Weather & replay

FIS-B weather is free on both, forever, no subscription on either side. Weather replay is supported in both ecosystems, so the Stratus 4 gives up nothing here while adding open-app flexibility on top.

AHRS / backup attitude

Sentry, Sentry Plus, and Stratus 4 all provide backup attitude; the Sentry Mini does not, that's the Mini's biggest sacrifice at $399. Among the units that have it, the Stratus 4 feeds the same backup attitude/synthetic vision into whatever GDL90 app you fly, not just ForeFlight. Portable AHRS is a backup aid, not a certified instrument; a bumped or sliding glareshield unit will momentarily skew the solution, so mounting stability matters for all of them equally.

CO detection

Sentry and Sentry Plus only have a built-in carbon monoxide detector with in-app alarm, a genuine advantage, and the one place a Sentry clearly leads the Stratus on safety. The Stratus 4 has none (Appareo's position: carry a dedicated CO detector). The honest trade: a standalone panel-mount or clip CO detector runs $30 to $200, works in any aircraft you fly, and never expires when you change EFBs, so most pilots are better served pairing a dedicated CO detector with a Stratus 4 than buying into ForeFlight lock-in for the sensor. The Sentry CO sensor is rated for about 10 years of sensor lifespan, not calibration-free forever.

Battery

Sentry Plus up to 18 hr sealed; Sentry ~12 hr sealed; Stratus 4 ~8 hr but user-replaceable (the only one here, a spare battery in the flight bag means an effectively unlimited duty day, and a cheap fix years from now when the cell ages instead of a dead, sealed-shut receiver). The Sentry Mini has no battery at all (bus/USB-powered only, fine for owned aircraft with USB power, a real limitation for renters). The Sentry Plus's 18 hr sealed run wins a single long day, but the Stratus 4's swappable pack wins the long haul of ownership.

Display & controls

Sentry Plus has an OLED status display; the Stratus 4 has a full-color touchscreen (settings/status on-device without opening the app); Sentry and Mini use LED indicators only. This one is a clean win for the Stratus 4.

Extras

Stratus 4 adds Apple Find My support (leave-it-in-the-plane insurance) and auto power on/off with external power. Sentry Plus adds a flight data recorder with g-meter and automatic tracklog import to ForeFlight; the Stratus 4 records flight data with tracklog import to compatible apps. All use WAAS-grade GPS; Sentry Plus adds multi-constellation/Galileo fallback.

Stratus 3 vs Sentry, and Why That's No Longer the Right Question

The Stratus 3 is discontinued and out of stock at Appareo. Some roundups still list it at $749 as if buyable new, they're stale. A clean used Stratus 3 at the right price is still a capable dual-band GDL90 receiver (open-app advantage included), but you inherit an aging, non-replaceable battery, no touchscreen, no Find My, and a shrinking support runway.

Appareo's $250 trade-in credit for a Stratus 3 toward a Stratus 4 effectively makes the 4 a $599 upgrade, which undercuts the used-market math for most sellers and buyers. Bottom line: if you can get a used Stratus 3 well under about $400, it's defensible; otherwise buy the Stratus 4 (or trade up).

Pricing & What's in the Box

2026 pricing: Sentry Mini ~$399, Sentry ~$599, Sentry Plus ~$799, Stratus 4 $849. Suction-cup mounts and cables are included on both lines; check included-mount fit for your glareshield. The Sentry line is a little cheaper at every tier, but the roughly $50 gap between the Stratus 4 and the Sentry Plus buys app freedom, the touchscreen, and the swappable battery, which is what protects the purchase over its multi-year life. The Sentry Plus's $50 saving buys CO detection, FLARM, and an 18-hr battery, features a minority of pilots will actually use, on a receiver that can never leave ForeFlight. For the money, the Stratus 4 is the better value.

View the Stratus 4 at Pilot Mall ($849) →

Who Should Buy Which

• The ForeFlight-first pilot (owner, iPad) → Stratus 4 ($849). You'll get the same dual-band traffic, subscription-free weather, and AHRS inside ForeFlight that a Sentry gives you, plus a touchscreen, a swappable battery, Find My, and the freedom to keep the receiver if you ever add Garmin Pilot or an Android tablet. The Sentry Plus's deeper in-app integration (CO alarm, FLARM) is real, but it's not worth chaining an $800 receiver to one app for most pilots.
• Garmin Pilot or any Android user → Stratus 4 ($849), no contest. A Sentry literally cannot pair with your app or OS. If you're all-in on the Garmin ecosystem (aera, G3X), the Garmin GDL 50 ($850) is the native-fit alternative we also stock.
• Renter / CFI / club pilot → Stratus 4. You don't control which EFB is on the other yoke; GDL90 pairs with whatever the day brings, and the swappable battery survives back-to-back lesson days. A Sentry would strand you the moment a student or club aircraft runs a different app.
• Budget buyer with USB power, VFR, mostly ForeFlight → Stratus 4 still. The Sentry Mini (~$399) is the cheapest dual-band weather/traffic in either lineup, but you give up the battery, AHRS, CO detection, the touchscreen, and any app other than ForeFlight. If budget is truly the constraint, a used open-GDL90 unit or saving toward the Stratus 4 leaves you with a receiver you won't have to replace the first time your flying changes.
• IFR cross-country / twin pilot wanting backup attitude → Stratus 4 (confirm your EFB consumes Stratus AHRS first), or the Garmin GDL 50 if you fly the Garmin ecosystem. Both give you backup attitude without tying you to a single app.
• Anyone holding a Stratus 3 → trade it up. Appareo's $250 credit makes the Stratus 4 effectively $599.

Overall: buy the Stratus 4, or the Garmin GDL 50 if you live in the Garmin ecosystem. The Sentry Plus genuinely wins on a few specs (CO detection, FLARM, an 18-hr sealed battery, and a slightly lower price), and we won't pretend otherwise. But a $400 to $850 receiver should outlive your current app subscription, and only the open-GDL90 Stratus 4 survives an app change while matching the Sentry on the data that keeps you safe in the air. The Sentry Plus is the better device inside ForeFlight; the Stratus 4 is the better receiver to own, which is why it's the one to buy.

Frequently Asked Questions

Does the Sentry work with any app besides ForeFlight, and what happens if I switch to Garmin Pilot or an Android EFB later?

No. All Sentry models (Mini, Sentry, Sentry Plus) work exclusively with ForeFlight, which runs only on iOS. If you later switch to Garmin Pilot, FlyQ, or any Android EFB, the Sentry becomes a paperweight and you'll need new hardware, the Stratus 4's open GDL90 output is specifically the insurance against that, which is why we recommend the Stratus 4 over the Sentry for almost everyone.

Stratus 3 is discontinued, should I buy a used Stratus 3 or pay up for the Stratus 4?

The Stratus 3 is out of stock at Appareo and no longer sold new. A used unit well under about $400 is still a capable open-GDL90 receiver, but you inherit an aging, non-replaceable battery and a shrinking support runway. If you already own a Stratus 3, Appareo's $250 trade-in credit toward a new Stratus 4 usually beats selling it used.

Is the Sentry's built-in CO detector worth it, and does the sensor expire over time?

It's the one area where a Sentry clearly leads: an in-app CO alarm is a genuine life-safety feature the Stratus doesn't offer, and it matters most in older aircraft with cabin heat off the exhaust shroud. But you don't need to lock yourself to ForeFlight to get it, a dedicated $30 to $200 CO detector works in any aircraft and pairs fine with a Stratus 4, which is why we still steer most pilots to the Stratus 4 plus a standalone CO detector. The Sentry's electrochemical sensor is rated for roughly 10 years of life rather than requiring periodic calibration, so plan on it lasting the realistic life of the device.

Which lasts longer in real flying: Sentry Plus's 18-hour sealed battery or Stratus 4's 8-hour user-replaceable battery?

On a single charge, the Sentry Plus wins decisively, up to 18 hours covers a full flying weekend. But the Stratus 4 is the only receiver here with a user-swappable battery, so a charged spare in your flight bag gives it effectively unlimited endurance and a cheap fix years from now when the cell ages, instead of a sealed receiver you have to replace. Over the life of the receiver, the swappable battery is the more practical design.

Which gives a more reliable backup attitude (AHRS) on the glareshield, and does mounting matter?

Sentry, Sentry Plus, and Stratus 4 all provide comparable portable AHRS for backup attitude and synthetic vision; the Sentry Mini has none. The Stratus 4's advantage is that it feeds that attitude into any GDL90 app, not just ForeFlight. For all of them, a bumped or sliding unit will momentarily skew the attitude solution, mount it firmly, and treat portable AHRS as a backup aid, never a certified instrument replacement.

Do either require a subscription for ADS-B weather and traffic, and do both work on iPad, iPhone, or Android?

Neither requires any subscription, FIS-B weather and ADS-B traffic are free FAA broadcasts on both. The Sentry works only with ForeFlight on iPad/iPhone (no Android); the Stratus 4 works on iOS and Android through ForeFlight, Garmin Pilot, FlyQ, WingX, FltPlan Go, and Stratus Insight, which is why it's the more flexible buy.

Final Word

Same dual-band traffic, same subscription-free weather, but only one of these receivers keeps working when your flying, or your tablet, changes. For nearly every pilot that's the Stratus 4; for the Garmin-ecosystem pilot it's the Garmin GDL 50. The Sentry Plus is a fine device if you'll never leave ForeFlight, but it's a riskier purchase on a receiver you'll own for years, which is why we point you to the open-ecosystem option instead. Shop the Stratus 4 at Pilot Mall, or compare the rest of our portable ADS-B receivers. Questions about EFB compatibility? Our team flies this gear, contact us.