Rarity uses Air Ponyville’s little plane to commute because it’s the fastest way to get from Ponyville to any city of actual size. She doesn’t like that rickety little cramped thing, but she can tolerate it - so long as the door stays closed. She cannot fathom what makes Rainbow Dash or Fluttershy willingly throw themselves out of that plane.
 
Spike doesn’t get the chance to fly much, because he’s a four-foot-tall talking dragon thing and an abomination of science; people might get the wrong idea. But when he does have to travel with the girls to Canterlot on business, he relishes the chance, even if this plane is a lot smaller and more shaky than he imagined.
 
But the two of them handled the flight just fine together. Right up until some rude individual came out of nowhere and shot the plane’s wing off. Before they know it, Dash has crammed Rarity into a parachute, ordered the two of them to hold on to each other, and pulled them both out into open sky.
 
Dash was able to pull their parachute open and then dropped away, leaving them clinging to each other for dear life. They don’t dare look down to see if there’s any sign of their friends. And the dark shape that ruined the plane is turning back towards them…
 
(Commission for Air Ponyville from Carnifex with my thanks)