Which aircraft have wifi on board?
Unfortunately, this cannot be said in general. Here it is recommended to visit the website of the airline. Older aircraft usually do not have Wi-Fi on board, and newer ones only have it if the airline orders it. The antenna for the satellite connection weighs around 200 kg and sits on top of the fuselage of an Airbus A320-neo. That's what prompted Lufthansa, for example, to equip its new aircraft without Wifi in 2019. Lufthansa, for example, has developed Flynet as its own service for its aircraft. More info is available from Lufthansa.