Now that WiFi is available on airlines, can we have WiFi active but cellular turned off? Trying to always connect to cell service from aircraft drains battery quickly!

I was just traveling, and the ailine was offering WiFi service. The iphone has an airplane mode which disables WiFi and cellular, which was fine in the "old days." Now with WiFi on planes I need to have WiFi on, but not cellular as it just drains the battery looking for service it can't find. I don't know how to disable cellular while keeping WiFi on. Maybe Apple could add a switch for cellular in a future update?

Dave