Rainbow Dash MAY be faster than a fighter jet, perhaps even more dangerous, but that's because she's unique prodigy; the fastest flier in all of Equestria, the only pony capable of a sonic rainboom, most powerful pegasi by default, etc. She's the exception, not the rule.
If it ever comes to a pegasus/jet-fighter aerial dogfight, I'll bet on a jet fighter any day.
Thunderlane: "That's why we won't fight fair, if that ever happens. Hit those contraptions while they're on the ground with a few well-placed lightning bolts to the fuel tanks...or just to the ammo depots on the airbase. Maybe just stay low and avoid their fancy radar things, then have a team of pegasi whip up a tornado when the flyboys get into OUR airspace, while we burn away and let nature do its own work. It's a longshot, but we have ways of hitting back."
Up there at 11 o'clock -- it looks like a -- pony! **** Hi Rarity, it's me. -- It's who? Oh, I'm sorry, it is me. You asked, what you're asking about, it's me. ... It's not a piece of equipment ... it's ME!
You know... one of the coolest things about this fandom is how fast it started. For example, what you might believe to be a somewhat random desire has already been satisfied as early as the first summer of the fandom:
Ghost Eye: "Garuda Team, we have a friendly pony under attack, move to intercept." Shamrock: "You sure about that, Ghost Eye? I can see her on radar. She's flying circles around those bogeys." Ghost Eye: "Orders from Air Defense command; get on it, Garuda Team." Shamrock: "If you say so."
Pilot1: Angle 6 to control Command: Go ahead Angle Pilot1: We have a rainbow pony with wings flying over U.S Airspace, should I engage? Command: Negative, repeat Negative, do not fire, she's friendly! Pilot1: Copy command, breaking of attack, Angle 6 returning to base, out.