Typing on a Plane: WriteAmp With No Network
The truest test of a local app is a flight. Not a benchmark, not a spec sheet, a six-hour flight with no Wi-Fi, a drained phone, and a MacBook you're hoping will hold out. That's where "on-device" stops being a feature and starts being the difference between working and staring at a screen.
I wrote WriteAmp to pass that exact test, so let me tell you what actually happens when you take it on a plane, and where the honest limits are.
The short version
Once WriteAmp is set up, suggestions work with the network fully off. No Wi-Fi, no hotspot, no cellular, nothing. You type, the model on your Mac finishes your sentence, you press Tab, and not one byte of it ever wanted the internet. I've done it, on a flight, writing a draft that sat on my Mac the whole way.
That's the whole point of running the model locally instead of in a server. There's nothing to reach out to, so there's nothing to wait for.
What has to happen first
Here's the honest part, the part I don't hide. For the plane to work, you've got to do a little setup on the ground, because three things need the network once, and only once.
That second step is the one I refuse to gloss over. Activation is network-required, and I've said so plainly in the network ledger. If you buy WriteAmp at the gate and try to activate it at 30,000 feet, it won't work, because the store has to say yes. The fix is boring and honest: activate before you fly. Everyone who buys the app is online at the moment they buy it, so this is a five-second step, not a burden. But it's a real network dependence, and I'd rather you know it than discover it.
What the plane is actually like
With those three things done, here's the plane experience. You open your editor, or Mail's offline drafts, or Notes, and you type. The gray suggestion appears, you press Tab when it fits, and the whole time the app is doing real work, reading the sentence, thinking, suggesting, all on the chip inside your Mac. It's genuinely a little strange the first time, because every AI thing you've ever used has needed a server, and this one just doesn't.
The engine is also built for the battery reality of a plane. If you picked the bigger model, WriteAmp quietly downshifts to the smallest one when you unplug, which I wrote about in the battery post. On a six-hour flight, that's the difference between landing with power and landing with a dead Mac.
Where the network actually matters
Let me be precise about the boundaries, because "works offline" should mean something specific. The suggestion engine is offline, forever, once the model is downloaded. But three things still want a connection when they can get one.
The app checks for updates now and then, so you get fixes without hunting. The license re-verifies quietly every so often, so a refund or a revoked key takes effect. And if you haven't downloaded a new language model yet, that needs the network the first time. None of those touch the plane problem. On a flight, the suggestions work, the writing works, the history works, and the only thing you miss is an update you didn't need anyway.
The deeper reason this matters
Here's why I built it this way, and it's not really about planes. A tool that needs the network to think is a tool that can be taken away from you. The server goes down, the company changes its terms, the subscription lapses, and suddenly the thing you type into every day stops working. A tool that does its thinking on your Mac can't be taken away, because there's nothing to take. It's the same reason the one-time price exists, and the same reason a local model has no reason to phone home. Remove the server, and you remove the ability to cut you off.
The plane is the purest version of that argument. Thirty thousand feet up, no server in reach, and the app just works. That's not a feature I bolted on. It's the architecture.
The test
If you have WriteAmp, try it the next time you fly. Turn on airplane mode, open a draft, and type. If you've never flown with it, the trial is free for 30 days, and the setup takes five minutes on the ground before you board. The moment the plane doors close and the suggestions keep coming, you'll understand why I built this instead of renting a server.
The privacy page has the written version of what stays on your Mac, and the network ledger has the three exceptions. Between them, you can see the whole boundary before you ever leave the ground.
Sources
- WriteAmp terms: trial, license, and activation terms
On macOS 26+ Macs, Apple Intelligence mode stays free even after the trial ends — you always keep a working path to suggestions.
Written by Amit Ashwini, who builds WriteAmp and runs its marketing. More: why the Tab key beats the chat box · mini, midi, and max compared · benchmark methodology.