[Skarphol]

If you place a flight of four planes to take off from a flat field that isn't a runway, they will take off at the same time, allmost line abreast. Suitable fields are rare on the Slovakia map though. I'm not sure if there are any at all.
The trick is to place a flight on the map, and set the first waypoint to 'Takeoff'. Then that flights symbol will be moved to the closest runway. Then you have to grab that symbol and pull it to a suitable field, and the flight will take off from there. The flight will take off in the direction of the next waypoint. This trick allways work, but if the place you drag the flight to is not suitable for a takeoff, the planes will probably get their undercarriage torn off as they gather speed.
Placing the takeoff waypoint in a hillslope can be quite fun, as the planes will start rolling and sliding downhill before they try to take off.

If you don't pull the takeoff waypoint more than maybe a kilometer or so away (don't have the correct distance in my head) the flight will take off at the runway as usual.

Skarphol