Start with the terminal
At Gatwick, official Short Stay is a short walk, while Long Stay uses a free bus that the airport says usually takes around 10–12 minutes to the terminal. Allow additional time to park, reach a bus stop and wait for the service. Gatwick Mid Stay is about a six-minute walk but must be pre-booked.
At Heathrow, Terminal Parking offers a covered walk at Terminals 2, 3 and 5 in the current official overview. Park & Ride uses buses and is listed for all four terminals. Heathrow's Terminal 4 arrangements are affected by redevelopment; use the latest official directions before driving.
Use the filter as a constraint
If you cannot use a shuttle, choose “Walk only” in the comparison. The tool then shows only products whose official access description fits. If no option remains for your terminal, it says so instead of silently substituting a different car park.