S!
+1 to what Fjordmonkey said.
Taking off or landing, they're still the enemy and valid targets. Vulcher guilty as charged. And I welcome everyone to vulch me in return
War is hell etc. Just pick the not-so-close-to-the-fight -field and you're safe from vulching. Or if you must take off from the front field, fly low and fast away from the direction of fighting before starting to climb.
Mission editors CAN make vulching much harder if they choose so, placing heavy AAA around the airfields.