An excavation team searching for dozens of Spitfires buried in Burma at the end of the second world war has discovered a wooden crate that could hold one of the planes. But the crate – found during a dig in northern Burma – was full of muddy water, making it difficult to gauge precisely what it contained and how much damage the water has done.

David Cundall, a 63-year-old farmer, private pilot and aircraft hunter from Lincolnshire, who has been searching for the planes for 17 years, described the discovery as "very encouraging". Cundall, who is leading a team of aviation enthusiasts, archaeologists and geophysicists bankrolled by the online military gaming company Wargaming.net, said in Rangoon that he was very excited. "It will take some time to pump the water out," he said, "but I do expect all aircraft to be in very good condition."

The main focus of the team's efforts is a site close to the runway at Rangoon international airport, where, it believes, as many as 36 Spitfires could be interred.

Speaking about the mission last week as he prepared to fly to Burma, Cundall insisted he would find his planes. "We will have a box on the surface, you can open the doors, and you will see the aircraft inside," he said. "These are 100% original Spitfires that have been buried for 67 years, and they will still be shining."