A WC54 turned up in Cambridge, England, where the seller was persuaded to part with it for about $11,000 after being told that it would return to the United States when the anniversary gathering dispersed. After seven decades overseas, including a 30-year stint in the postwar Greek army, it was time finally time for the old soldier to come home.

The human participants at D-Day tributes are, predictably, less durable.

“This is the last year there will be serious veteran involvement,” said Preston Isaac of North Devon, England, who helped lead a group of more than 130 vehicles from the 5,000-member Military Vehicle Trust, a British collector club. With most D-Day veterans in their 80s or 90s by now, attendance by actual participants of the invasion at these events are increasingly rare. The few hundred who came for the 70th were treated like rock stars by camera-clicking crowds.

“After this, I don’t know what’s going to happen,” Mr. Isaac mused about interest in the event. “But it’s not dropping off like you’d think.”

The demand for vintage military vehicles, especially those from World War II, has jumped in recent years, mirroring the trend in classic cars. The legend of the $500 jeep in a crate is just that; pristine wartime jeeps, of which Willys-Overland and Ford produced some 645,000, sell for $15,000-$20,000 on specialist websites like England’s popular Milweb.net. A restored Sherman tank can command more than $300,000.

“A lot of people look at it as an investment,” said Rodney Rushton, a Briton who has been coming to Normandy since 1974 and this year drove a 1942 Chevrolet G506 heavy truck to the commemoration. “The price of classic cars went through the roof years ago, and jeeps were always the poor cousin. Now the boot is on the other foot.”

With a cruising speed of around 40 m.p.h. and three small seats wedged into a body that is shorter and narrower than the original Mazda Miata, a war-era jeep is hardly what most car collectors would consider exotic or luxurious. Larger military vehicles tend to be even slower, and they greedily drink Europe’s $9-a-gallon gasoline. Parts can be difficult to find for obscure vehicles, and they require lots of storage space on a Continent known for its small houses crammed into tightly packed cities.

Mr. Isaacs of the vehicle trust said that the buyers of these vehicles fell into three categories: those who wanted the vehicles their fathers or grandfathers drove in the war; those who just had a fondness for odd machines, especially some of the obscure vehicles made for the British army, which contracted for vehicles from more than 600 companies during World War II; and those, he said, who “want to look like John Wayne with their leg hanging out of the jeep and chewing a cigar.”