Spawning an aircraft in flight in the middle of a mission

[Galaga]

Hi all. I'm trying to create a mission where a hostile jet spawns during the mission to attack the players (the mission is a group of Cobra gunships attacking an airfield). I've read the Mr. Murray ArmA1 editing guide as well as several other things (such as this website's FAQ and beginner guides) but unfortunately I can't figure out how to get what I want to work.

I can do the trigger condition and the random timing easily enough but I don't know how to get the aircraft to spawn in the air, going fast, and pointed in the right direction. I think I know the basics on how to do each of these, but when I try to string them together the game doesn't even let me close the trigger box, complaining about one thing or another.

I considered just having a jet flying in an out of the way area of the map and then just use the trigger to relocate it to where I want it, but I'm using the Utes island map which doesn't really have the space.

I'm totally new to the editor and was a total failure at scripting/programming in the first place, so this is all unfortunately very difficult and confusing for me. At the same time though, I can't help but think I'm missing something stupidly easy/simplistic.