There's a couple of neat flying Pigeon mods! The Jetgion: adds a Jet engine option to the Pigeon. It's not inherently a flying car but useful for the next mod! https://www.beamng.com/resources/jetgion.27612/ The Fligeon: A Pigeon with wings driven by a propeller. Remove the prop and you can add the Jet engine from above mod! https://www.beamng.com/resources/fligeon-the-flying-pigeon.21652/ There's also the Wingeon a successor to the Fligeon. This mod turns the Wigeon into a flying beast. https://www.beamng.com/resources/wingeon-the-flying-wigeon.27686/ There's also a flying D-Series (although I am unsure if this fixed version still works) https://www.beamng.com/threads/fixed-pickup-hell.85123/ There was also flying Bolide at some point, a "fixed" appears in search but it appears that the thread was deleted.
Not to sever your wings good sir, but I believe the term you are in search of is an 'aeroplane.' They operate solely as automobiles for the airways, is that not which you are inquiring? Ultimately I understand that few such add-ons presently exist within the repository, however I yet advocate you examine further the aforementioned avenue of search.
The D-Series still works for me. I don't use it often but it works. ALSO there's the Fort Focus, it comes with a flying version of it. And it works really well and it's cool --- Post updated --- I think the Ford Focus mod is called the Fort Fucos or Fucus or perhaps I am misremembering. I will link it if I can find it.
My good sir I believe I have not made myself clear; I said I wanted an aeroplane made out of an automotive.