I've noticed that airline wifi doesn't block DNS traffic. You can likely accomplish the same thing with a DNS tunnel like Iodine (https://github.com/yarrick/iodine).

Sometimes they just redirect ALL DNS traffic to their little portal until you sign in/up.

Many years ago, I noticed I could browse the Google Play Store on a flight WiFi without paying for it. No images would load and no apps would download, but I could browse through app listings and read reviews.

Would this be related to DNS?

Probably not. I bet something in Android didn't work properly until they whitelisted some Google domains — for example, maybe it didn't detect the Internet connection when the user paid for it, or maybe something on the entertainment tablets broke (I don't know if they usually run Android or something else).

This seems likely. ~6 years ago on a Delta flight I noticed that I could use Google and view cached pages without paying for WiFi. I managed to catch up on the news on my flight…

I see you found that TCP relay- I've been dying to try it but I've heard of people successfully using it

https://github.com/aleixrodriala/wa-tunnel

I happened to have had a flight a day or two after the first beta of Apple’s Private Relay a year or two ago. I was able to use free WiFi the entire flight. Presumably because whatever they whitelisted for iMessage and/or push notifications covered that as well. They had blocked it before my return flight days later. ¯\_(ツ)_/¯

Huh. Maybe this explains why my "messaging only" wifi on Virgin Atlantic a few weeks ago gave me full, slow, internet access?

Instead of “wow, cool” my first reaction is “free messaging is a great perk, if this is abused they will shut it down”. I guess my hacker days are behind me.

Airlines already introduce free WiFi to everyone for free. JetBlue does it, Delta also does it for continental flights. Eventually all will, as there is more competition in the tech and prices drop.

I've not read the EULA but why not just have an actual IP router?

Pay the signup charge, and also stand up a wifi network. Call it "Foo discounted" if the plane's SSID is "Foo". Put up a captive portal that lets the user claim various "discounts", like veteran, senior, child, etc. No matter what they choose, charge them $2 via a payment page. Once you've been made whole on the service cost, future visitors get a notice that "all discounts have been claimed, please use Foo".

Now you have free internet and all those using your router/portal have $2 internet. The upstream bandwidth is certainly atrocious so you will easily be able to multiplex all the data onto your connection.

Bundle it into a RPi kind of device (has to look finished, like a music player or smth, to get past security) so that you can continue to operate the device even when tray tables have to go up, when you go to the bathroom, etc.

I find it extremely doubtful that the airplane has WIPS or WIDS that will deassociate connections to your rogue wifi. And after all, are you not allowed to have a LAN party?

I believe this is the approach that Flighty (https://flightyapp.com/) uses to send flight updates while on non-paid Wifi.

Flighty leverages the Apple Push Notification Service (APN), which the iMessage infrastructure also uses. It's why you can receive notifications in flight but can't act on them.

Way back in the day a lot of authenticated wifi firewalls did enable DNS requests to pass through, or at least to resolve using their DNS server, without being authenticated.

Someone smart created a TCP-over-DNS tunneling tool that I had a lot of great experience with, at least for more simple news websites of the day.

https://analogbit.com/software/tcp-over-dns/

A more current alternative: https://github.com/yarrick/iodine

Tried this on a flight 4 years ago -- I got to SSH into a machine and read my mails, it felt like I was connecting from a space ship... so funny but not actually usable to browse the web or do any actual work ;-)