Most WRD players use automatic plane evac. This means their planes evac after they’ve dropped their bombs or otherwise used up their main armament, without waiting for player orders to that effect. It minimizes mistakes and decreases the micro needed when using bombers.
A flaw of automatic evac is that sometimes you want bombers to stick around after dropping their payload. This is often the case for multiroles – a C-Hornet for example has great ECM and missiles lethal enough to act as a fighter, but you can get silly situations where the hornet charges an enemy superheavy, kills it, and then can’t attack a nearby enemy bomber because it was forced into an evac winchester.
I use a lot of multiroles, so I’ve gotten used to playing with manual evac. If you disable automatic evac, you will at first often forget about your planes and leave them circling over enemy AA, ammo expended and waiting to die. The main trick to avoid this is to get in the habit of queuing evacs – you can reproduce the effect of automatic evac if you press shift+E (evac hotkey) after every attack order you give. Sometimes it helps to queue it after normal move orders too: I usually give a move order with the intent to follow it up with something more specific, and if I end up forgetting to followup, it is safer to retire the plane than to keep it on the map on the off-chance that I notice it before it tips the opponent off.
A failure mode of queued evac is that, for planes with guns, the evac will only happen after the gun run. The Soviet Su-24M for example has 30 bombs and a gun, and you always want to drop the bombs and immediately evac, not drop the bombs and do a pointless risky gun run and then evac. The solution here is to disable the gun so that the plane doesn’t attempt to use it, but rather just drops the bombs and cleanly evacs.
There’s one more pitfall! The gun has to be disabled before the target is chosen and the evac is queued. If you order an attack, queue and evac, and then disable the gun, the plane will not evac. It took me a long time to notice this, and for my first year of using manual evac I kept having inexplicable failures due to it. Presumably when you order an attack, the order gets decomposed in its elements and put on a stack ([drop bombs], [use gun]). Adding the evac order, the stack looks like ([drop bombs], [use gun], [evac]), but a disabled gun makes it impossible to clear the second element and reach the third.
Regardless if my speculation about the cause is correct, the fact of the matter is, you must disable the gun before giving the attack order, not after – otherwise a queued evac will not work.