The fire at Luton Airport car park was started accidentally due to a vehicle fault, Sky News understands.
A man in his 30s has been arrested on suspicion of criminal damage in connection to the incident on 10 October.
It is believed the man, who has been released on bail, was arrested as a precaution and the police investigation so far suggests the fire started accidentally due to a vehicle fault.
Earlier this month Andrew Hopkinson, chief fire officer with Bedfordshire Fire and Rescue Service, said as many as 1,500 vehicles were in the car park at the time - with up to 1,200 believed to be damaged.
A Bedfordshire Police spokesman said: "Police arrested a man in his 30s on suspicion of criminal damage in connection to their investigation into a significant fire in a car park at London Luton Airport on Tuesday (10 October).
"We are carrying out a thorough and diligent investigation into all potential lines of enquiry, as should be expected after such a major event.
"The man has been released on bail while our enquiries continue."
Luton Airport said last week that it was "unlikely" that any vehicles would be "salvageable" following the fire, which caused a partial collapse of the car park.
It said it had provided the Motor Insurers' Bureau (MIB) with the registration details of 1,405 vehicles and, along with its parking provider APCOA, it had responded to almost 16,500 customer queries since the fire.
An airport spokesperson said it recognised it has been an "extremely distressing" time for those affected and it was working with the Association of British Insurers to establish the possibility of safely retrieving any personal items from the vehicles.