Not sure if I understand what you're saying but CH's offline key works for/with all trainers here, no matter which one you want to use. One key to rule them all.
Just make sure to use the offline key creator tool (Link) on the very PC you use on your flight and follow the description provided. After that, cut its WiFi or LAN and launch a trainer to verify that the key is actually working.
[Edited by Taurusplopp, 10/4/2019 6:03:16 AM]
I know that I can follow that process for using them offline, just wondering if anyone, knowing in advance their flight has had wifi, and decided not to bother. I was more after banter, e.g "Yeah I used the trainer on cod ww2 campaign but quickly closed it when I realised the person next to me on my Japan flight was Japanese" (Which happened to me and I felt a bit bad about it)