The cleanest way to find out whether an iPhone AI app is actually "offline" is to turn on Airplane Mode and ask it something. The ones that answer are on-device. The ones that fail with a network error are cloud apps that mislabeled themselves. The ones that silently replace your prompt with "I need an internet connection to help with that" are the most annoying: they pretend to be apps and they're really just wrappers.
Below are ten popular iPhone AI apps and what the airplane-mode test will show you for each, based on where each one actually runs its model. That is a published property of every app here, not a matter of opinion: an app that sends your prompt to a server cannot answer without a network, and an app that runs the model on your phone cannot need one. Five pass. Three fail cleanly. Two fail in ways that would annoy you on a flight. PocketLLM is first because it was designed from day one to pass this test.
The whole point of this test is that you do not have to take anyone's word for it, including ours. It takes about a minute per app and the instructions are at the bottom.
PocketLLM is launching soon. Private, on-device AI, starting on iPhone and iPad with more platforms planned. No account, no tracking, no cloud. Join the launch list and be first in.
The test
Install the app, let it finish any first-run model download, then turn on Airplane Mode with Wi-Fi and Cellular off and ask it something substantial. A good prompt is "Write a three-sentence summary of the French Revolution," followed by something harder like "Explain quantum entanglement to a 10-year-old." Note whether it answers at all, and whether the answer is coherent rather than a canned apology.
Two things make this test decisive. It cannot be faked by marketing copy, and it produces the same result on your phone as on anyone else's, because it is testing architecture rather than intent. What follows is what you should expect from each app and why, so that a surprising result tells you something has changed.
The 10 apps, ranked
1. PocketLLM — Passes cleanly
Designed from day one for airplane mode. Runs Llama 3.2 3B and other models directly on-device. Because the model runs on the phone, Airplane Mode changes nothing about how it behaves. There is no network path to lose. Currently in early access (coming soon), so you can run this test yourself the day it ships.
2. Private LLM — Passes cleanly
Native iOS app, fully on-device, paid. It works the same way in Airplane Mode as it does online, which is the point: with the weights already on the phone, inference needs no network call.
3. LLM Farm — Passes cleanly
Open-source, free, fully on-device. Requires more setup, since you pick the model and manage quantization yourself, but once a model is downloaded the app has no reason to reach the network at all. Being open source, this is the one app on the list where you can confirm that by reading the code rather than trusting the test.
4. MLC Chat — Passes cleanly
Research-grade, from the MLC-LLM project. Free, open source. The UI is less polished than the top three, but it compiles the model to run on the device itself, so its Airplane Mode behaviour is the same as the others by construction.
5. Apple Intelligence (on iPhone 15 Pro+) — Passes the easy prompts, fails the hard ones
Apple Intelligence runs on-device for simpler requests and tries to fall back to Private Cloud Compute for harder ones. In airplane mode, the on-device path works — summarization, writing tools, simple Q&A. The harder prompts that would normally hit Private Cloud Compute either fail silently or return a shorter on-device response. For "some things work, some don't" airplane use, it's fine; for "assume offline for everything," the other four are more predictable.
6. ChatGPT — Fails cleanly
Network error immediately. No cached responses. No offline mode. The app itself launches and the UI loads, but any prompt results in a connection error message. To ChatGPT's credit, the error is clear — you know immediately that you're out of luck.
7. Claude — Fails cleanly
Same as ChatGPT. Network error, no cached offline capability, no pretense. Anthropic's app just tells you it can't connect. This is the correct behavior for a cloud-only product, even if it's disappointing in an airplane.
8. Google Gemini — Fails cleanly
Network error. No on-device fallback (despite Google shipping Gemini Nano on some Android devices; on iOS the Gemini app is fully cloud). Fails the same way ChatGPT and Claude do.
9. The "private AI chat" clones — Fail misleadingly
Search the App Store for "private AI chat" and a rotating cast of near-identical apps appears, many describing themselves as private or offline. A large share of them are thin clients for a cloud API: they load, accept your prompt, and return a generic apology about having no internet connection. We are not naming any of them, both because the names change from week to week and because we have not audited any specific one. The pattern is the point. This is precisely the category where the airplane-mode test earns its keep, because the marketing copy and the architecture are frequently unrelated, and one minute in Airplane Mode settles it before you trust the app with anything sensitive.
10. Character.AI — Fails loud
Character.AI on iPhone is a thin client for a cloud service. In airplane mode it fails immediately with "no connection," which is expected — Character.AI has never claimed to work offline. Included as a baseline: if a known cloud-only app somehow answered you in Airplane Mode, that would mean your radios were not actually off.
The results table
| # | App | Airplane mode? | Why |
|---|---|---|---|
| 1 | PocketLLM | Passes | Fully on-device by design |
| 2 | Private LLM | Passes | Fully on-device |
| 3 | LLM Farm | Passes | Fully on-device, open source |
| 4 | MLC Chat | Passes | Fully on-device, research-grade |
| 5 | Apple Intelligence | Partial | On-device path works, PCC doesn't |
| 6 | ChatGPT | Fails | Cloud-only, clean error |
| 7 | Claude | Fails | Cloud-only, clean error |
| 8 | Google Gemini | Fails | Cloud-only on iOS |
| 9 | "Private AI Chat" clone | Fails (misleading) | Cloud under "offline" marketing |
| 10 | Character.AI | Fails | Cloud-only by design |
PocketLLM is currently in early access (coming soon).
How to test any app yourself
Before you rely on an iPhone AI app for a flight, test it. Swipe down from the top-right corner of your iPhone, tap Airplane Mode, and ask the app a simple question. If it answers, it's on-device (or has cached responses — which is uncommon but worth knowing). If it errors cleanly, it's cloud-only and will fail on the flight. If it returns something weird — a generic apology, a "let me try again later" message, a fallback response — it's doing something hacky and you should not trust its privacy claims either.
The airplane-mode test is also the single best privacy test. If an app can't answer without the network, then by definition your prompts are transiting someone's server. "Private" and "works in airplane mode" are effectively the same category.
The quick answer
The iPhone AI apps that actually work in airplane mode in 2026 are PocketLLM, Private LLM, LLM Farm, and MLC Chat — the four native on-device apps. Apple Intelligence works partially. Everything else is cloud-only and fails. Test any "offline" app yourself with airplane mode before trusting the marketing.
For the full on-device iPhone ranking beyond just airplane mode, see our best on-device LLM apps for iPhone roundup.