What does "fly out the back on to the A320" mean in the following sentence?

Question

“I mean it’s almost as if they don’t want to see their dearly departed fly out the back on to the A320”

This is from "The Inbetweeners E03S01"

Simon has driven into a funeral cortege, right behind the hearse, and in front of the chief mourners' car. There are flowers spelling the word 'DAD' inside the hearse. Will looks behind and sees a car with a woman crying in the back and a hard-looking man red with rage staring out from the front passenger seat.

Answer 1

Favorite Answer

It's sarcasm after one of the boys is complaining that the hearse is driving too slowly. Will sarcastically suggests that the mourners do not want to see the coffin fall out of the back of a speeding hearse, which of course they don't.

Answer 2

I haven't seen this but I suppose they are talking about the possibility of the coffin falling out of the hearse onto the A320 which is a road. An A road is a major road which is more important than a B road.