I'm not usually one to enjoy mobile games much and I'm very picky when it comes to any aviation themed games but I haven't been able to put down "World of Airports" since I stumbled across it a few days ago. It lets you manage real airports with quite real ops, so the aircraft are accurate and have correct liveries and airlines for the geography. The graphics are very realistic and create a nice atmosphere. You start at Innsbruck and there's a day/night cycle and dynamic weather - right now it's snowing in-game for me. When temperatures drop low the aircraft even start to get de-iced before pushback.

Great way to pass the time during those long cruise phases. For me it's the right amount of engagement without being too shallow or too micro-management focused. So far I've been able to play without ever hitting a "they pressure you into micro-transactions to enjoy the game" moments. 

If anyone is interested - you can play on your phone and tablet and download via your respective store for free, more info here (the in-game graphics actually look much better than on their website on my iPad): World of Airports!

Not affiliated with this in any way but thought people might enjoy it as much as I do.