Like Brian Drummond, I'm not aware of car key fobs using IR. A significant change in key fobs is the move from push-button fobs, where the user presses a button sending a burst of RF from the key fob to the car locking or unlocking it, to keyless entry fobs, where the user just stands near the car which unlocks without needing to press a button. Walking away from the car locks it.
This works by the car continually sending out low power (hence short range) RF interrogation pulses to which the key fob responds (also by RF). Unfortunately this design is susceptible to an attack where car thieves uses a receiver and transmitter pair to boost the range of the interrogation pulses allowing the key fob to unlock the car at a greater than normal range e.g. when the key fob is inside a home or other building.
When TV remotes use IR they generate it with IR LEDs, not lasers. IR LEDs work in the same way as any other LED but use semiconductor materials that generate IR rather than visible or UV light. Early TV remotes could use ultrasonic transmitters or even be wired with a long lead running to the TV. Remotes can also use RF. My current TV remote uses Bluetooth.