Their rocket exhaust as they're being fired would slow the planes down, rather than providing a boost
For the same reason, cars have exhaust on the rear so that they can go much faster forward than backward
Edit: /s since you apparently need it after every joke. I know that missiles aren't really fired, they detach and then propel themselves. Also, anyone who's ever idled their car on a flat surface knows that the exhaust thrust cannot even overcome rolling resistance.
Ackshually they do this, not with cars but, with WW2 era prop planes.
The Spitfire for example:
The Merlin consumed an enormous volume of air at full power (equivalent to the volume of a single-decker bus per minute), and with the exhaust gases exiting at 1,300 mph (2,100 km/h) it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways.
During tests, 70 pounds-force (310 N; 32 kgf) thrust at 300 mph (480 km/h), or roughly 70 hp (52 kW) was obtained, which increased the level maximum speed of the Spitfire by 10 mph (16 km/h) to 360 mph (580 km/h). The first versions of the ejector exhausts featured round outlets, while subsequent versions of the system used "fishtail" style outlets, which marginally increased thrust and reduced exhaust glare for night flying.
Torque doesn't exist.
Cars move because of the exhaust gasses.
"What about trucks with an exhaust that points up?" I hear you ask, well why are they always bent over at the top to point backwards?
Tractors that have an exhaust on the top use it to keep the tractor on the ground, otherwise the forces of dragging things would cause the tractor to float off the ground. But the exhaust is pointed backwards slightly, other wise it wouldn't move. The small backwards pointing force explains why tractors are so slow.
Electric cars are CGI, and part of the conspiracy to hide the fact that torque doesn't exist.
My god, you're onto something here. That must also be why we evolved with backward facing asses, to ease our walks when we fart. Ventilated seats in your car? They help channel your farts to add nitro boost to your car's exhaust.
I forgot you need "/s" after every joke, even in joke communities. It is a reference to this greentext:
Let's give anon the benefit of the doubt. Perhaps they're an alien engineer from a planet that only knows rockets, disguised as a teenager to learn about our modes of transportation.
Rockets aren’t attached to the plane when they launch. They release then fire there rockets. It might be near instantaneous but missile thrust has no bearing on an airplane.
The rockets would need to accelerate in the opposite direction of their initial motion, thus a lot more energy would be needed to reach design velocity. That makes it necessary to carry a lot more fuel for the propellant and thus, the rocket can carry less explosives. For some moment the rocket would also have zero velocity.
On the analogy with the car: The exhaust gases do not carry enough momentum to actually have a nonneglibile effect.