Anyone know a working method to spawn AI planes?

Not sure if it's unintended or if the spawn manager doesn't work properly, but in very, very rare occasions, an AI plane can spawn in portal mode. After many matches in my own portal games, I have a rough criteria of what I think triggers it, and they are:

1. You have to be playing in El Alamein. They will not spawn in any other map, not even in the battle of the bulge.

2. It has to be WW2 era and you have to be playing as the Germans. if you're the US, they will never spawn.

3. This is probably something that doesn't trigger it, but every time an enemy AI plane spawned, I selected an aircraft as my initial vehicle when loaded into the game. 

Since November, I have encountered an AI plane in El Alamein a grand total of about 5-6 times, and that's when I still had faith in the devs that they were going to update the game so I was playing this a lot, just an idea of how rarely they spawn. Also, once they are shot down, they will not spawn for the remainder of the game, so savor your dogfight, because it's a one-time deal. However, there was an occasion where it first spawned a bomber, I shot it down after the pilot bailed, and later a fighter spawned which I also shot down; but that only happened once and then never again.  

Now I know DICE doesn't give a rat's a** about PvE, they made that message very clear when they barred us from getting the weekly rewards after teasing us for a single week making us think that we could; so I'm not gonna sit here and wait for them to update PvE, we'd get half life 3 and 4 before that happens. So basically, I want to know if anyone knows a sure-fire way to spawn these planes so I can engage in the single dogfight before I leave the match. 

TL;DR: want to know a sure method to spawn AI planes in portal.