Decide how you will be approaching the airport. London Heathrow Airport is located west of the city. If you're coming from the Cotswolds or West Country, take the M4 motorway toward London. From other directions, take the M25 ring road.
Look for signs for the airport terminals and get off the highway. Follow the M4 until you see signs for terminals 1, 2 and 3. Terminal 4 is located off of M25 going south, but just continue toward the first three even if you're flying out of terminal 4.
Fill up your gas tank to avoid extra charges. You will see a gas station as soon as you get off the M4 going toward the airport.
Continue toward the airport, and look for signs for the rental car lots. These signs are located near a high concentration of airport hotels on the Perimeter Road. From here you should have no problem finding the car rental return.
Look for signs particular to your rental car company. These include National, Hertz, Enterprise, Budget, Avis, Alamo, Season Car Hire, Europcar, Guy Salmon Prestige and Sixt.
Return the car, and follow the instructions of the rental car employee who will check the car for damages and other issues.
Take the shuttle bus from the rental car area to the airport terminals. Shuttles leave often but can sometimes be very crowded, especially during the holidays.
