@ace42x - depends what you engage the flight with. If you are in a Heavy Fighter with a lot of Firepower, you can dispatch them quite fast. Also, in order to lose minimum HP, you have to approach them correctly... front-side, like from 11 o'clock or 1 o'cloak... on a horizontal plane. This way, you are outside their gunners coverage and can dispatch 2 of them in a pass, going as i said, from 11 toward the flight, bank right/left a bit, and proceed towards 1 (and reverse)... I've seen quite a lot of players chasing them from behind... it's like the worst possible approach, exposing them to a lot of income gunner damage.
Sometimes, doing this properly (not receiving damage) and farming 1-2-3 flights of enemy bombers puts a lot of pressure on the enemy team to defend their CC from your team mates or from your own bomber flights (when you have a map with 2 CCs and got the other)
I can't recommend chasing bomber flights in fighters/multiroles that are slow, limited healthpool or, most important, lack the fire power... it can be done, but, as i said above, you must do it smartly.
From the perspective of someone that focuses on obtaining the medals, McCampbell, Ace and Marseille, the bombers are the free kills they need. From the perspective of a Heavy and a Fighter that wants to score a lot of points, again it's a lot of free kills towards achieving the "Destroy aerial targets" component towards and grade 1 performance. Multiroles are the only fighters that can't benefit from killing them towards performance grade, HOWEVER, for the F94D, BVPs... bomber flights are ideal towards completing the Golubev medal... also, cuz i just remembered, it's easy for Heavies to achieve the most difficult Gabreski medal by farming 10 kills.
Sometimes, depending on what you fly and what the enemy presence above the CC is, contesting their CC might not be the smartest decision. So, like most of the things in the game, situational awareness is vital.