You can't do this effectively, no matter how many transistors you connect.

The motor is intended to run at say 5 watts. That would require 200 mA at 24 V (5 W / 24 V), but to step that up from 3.3 V you need 1.5 A (5 W / 3.3 V).

The total amount of power that should be drawn through the GPIOs is 50 mA, and no more than 16 mA per pin. I believe if you try to go over this you risk damaging the pi. There's no way this could drive a motor big enough to power a car capable of carrying the pi around.

You could use a relay board and a separate power supply.

You can't do this effectively, no matter how many transistors you connect.

The motor is intended to run at say 5 watts. That would require 200 mA at 24 V (5 W / 24 V), but to step that up from 3.3 V you need 1.5 A (5 W / 3.3 V).

The total amount of power that should be drawn through the GPIOs is 50 mA, and no more than 16 mA per pin. I believe if you try to go over this you risk damaging the pi. There's no way this could drive a motor big enough to power a car capable of carrying the pi around.

Even if you used the 5 V supply and switched that somehow I think you would not have enough, since the input current is limited to 2 amps. You could use a relay board and a separate power supply.