You can leave early without any problem, and you will almost never get money back. Airport parking is sold as a block booking rather than a metered stay, so the barrier lets you out whenever you arrive and the price stays the same.
That is the short answer for self-park car parks. Meet and greet is the exception, and it is the one worth planning for.
Will the barrier let me out?
Yes. Your booking covers a window, and leaving before the end of that window is simply using less of it.
The barrier reads your number plate, matches it to an active booking, and lifts. Nothing about arriving early flags a problem, because the system is checking that you have a valid reservation rather than that you have used all of it.
This is the opposite of what people expect, largely because city car parks work the other way — they charge by the hour and calculate on exit. Airport parking does not.
Will I get a refund for the unused days?
Almost never, and it is worth understanding why rather than being annoyed by it.
When you book a fortnight, the operator takes that bay out of circulation for fourteen days. They cannot resell days eleven to fourteen to somebody else at short notice, so your early return does not free up anything they can monetise.
The price you paid also reflected the length of the booking. Longer stays carry a lower daily rate, so a refund calculated at the daily rate you paid would actually be a worse deal than rebooking the shorter stay would have been.
You did not buy fourteen days of parking. You bought a bay held for fourteen days, which is a different product.
Is it ever worth asking?
On a flexible rate, sometimes — if you know well in advance. If your flight is changed a week out and you can amend the booking before you travel, that is an amendment rather than an early return, and amendments are usually accommodated.
Deciding on the day, or ringing from the car park, is a different request. Some operators will offer a goodwill credit, most will not, and neither response is unreasonable.
The one thing worth doing is asking politely rather than assuming. It costs a phone call.
What about meet and greet?
This needs a phone call, and it is the real reason early returns matter. With meet and greet your car is in a compound some distance away, and a driver has to bring it to the terminal.
Operators schedule that around your stated return time. Landing six hours early and expecting the car to be waiting is asking for something they have not planned for.
Ring as soon as you know — from the departure gate if possible, or on landing. Most will accommodate a few hours with notice. Turning up unannounced can mean a long wait while a driver is found.
What if my return flight is moved forward?
Airlines occasionally bring a flight forward rather than delaying it, particularly when consolidating schedules.
If that happens, treat it like any other amendment. Contact the operator with the new details before you travel if you can. If you find out mid-trip, ring them — a flight number on the booking helps, since many meet and greet operators track arrivals automatically.
Does it affect the overstay policy?
No — early and late are handled completely differently.
Returning late can incur an overstay charge, often at a higher rate than the equivalent booked day. Returning early incurs nothing at all. The asymmetry exists because a late return occupies a bay somebody else may have booked, while an early return does not.
That is worth knowing when you choose your dates. If your return time is uncertain, booking the later date and coming back early costs you the unused days but avoids an overstay charge. Booking the earlier date and running over does not.
Should I book extra days deliberately?
Only if your return is genuinely uncertain. For a fixed flight, book the actual dates — the daily rate is low enough that padding a fortnight into sixteen days is poor value.
Where it makes sense is an open-ended trip, a cruise with a flexible return, or a business trip that might extend. In those cases the extra days are cheap insurance against an overstay charge, and you can leave early at no penalty.
A short summary
Self-park, leaving early — just drive out, no refund, no problem
Meet and greet, leaving early — ring ahead, ideally several hours
Flight moved forward before travel — amend the booking rather than returning early
Uncertain return — book the later date and come back early, which avoids overstay charges
Flexible rate — worth it when the return date might move, not just the departure
Compare terms as well as prices at Birmingham, Stansted or Luton — the cancellation and amendment policy matters more than a pound or two on the headline rate.