Motorists heading in and out of Masterton faced long delays on Saturday as an unprecedented number of spectators attended the Wings over Wairarapa airshow.
Up to 30,000 people are expected to attend the show over the weekend. Event director Liz Pollock says the numbers are unprecedented.
Police were advising of major traffic delays as motorists left Saturday's show.
Earlier, it was slow going along State Highway 2, as northbound vehicles clogged the roads in Featherston, Carterton and Greytown.
The 10th anniversary event showcases private collections of aircraft from the First and Second World Wars.
Thousands of spectators have been treated to air show jetabatics, demonstrations from the Royal New Zealand Air Force, and fighter and Spitfire displays at the Hood Aerodrome.
A repeat performance will be held on Sunday.