MUKILTEO — The Historic Flight Foundation is kicking off flying season with vintage warplane rides this Saturday. The museum’s B-25D Mitchell bomber, dubbed “Grumpy,” is headlining the Fly Day, which includes a barbecue and talks on the B-25 by a historian and two pilots.

Grumpy is scheduled to show its moves over Paine Field early Saturday afternoon.

“That always becomes a bit of a negotiation with the control tower, depending on what is going on in the air space,” said John Sessions, the Historic Flight Foundation’s founder and owner.

A couple of seats on the B-25’s 1 p.m. demo flight are still available for new members.

Grumpy is the oldest of the roughly 30 B-25s still flying. During World War II, airplane maker North American Aviation churned out nearly 10,000 of the nimble, twin-engine bombers from factories in Kansas and California.

The B-25 was a medium bomber, significantly smaller than better known heavy bombers, such as Boeing’s B-17 and B-29. Even so, the rugged airplane bristled with firepower. Different versions were equipped with machine guns, bombs, rockets and even a cannon on some models. Allied air forces used the Mitchell to rain destruction from low altitudes from Europe to the Pacific.

It costs about $2,500 to fly the airplane for one hour, Sessions said.

That is about evenly split between fuel and maintenance.

“The return on investment is subjective,” he said.

For people who are thrilled by the sight and sound of a vintage warbird zipping by overhead, the payoff cannot be matched. That passion prompted Sessions to start the Historic Flight Foundation in 2003.

The museum has grown steadily, adding to its aircraft collection. It currently has more than 400 members. Every airplane in the collection is in flying condition and dates from between 1927 and 1957.

Keeping the planes flying takes “an awful lot of work,” Sessions said.

A couple of cracked cylinders in one of Grumpy’s propeller engines grounded the bomber in April.

It had been scheduled to fly to Ohio to commemorate the 75th anniversary of the Doolittle Raid, an audacious bombing mission that boosted American morale in the dark days after its entry into World War II.

After Japan’s attack on Pearl Harbor, American forces were on the defensive across the Pacific Ocean. In the United States, there were concerns Japanese troops would invade the West Coast.

In a bold move, the U.S. Army Air Corps — the predecessor to today’s Air Force — stripped down 16 B-25s and put the land-based bombers on an aircraft carrier, the U.S.S. Hornet. The carrier brought the bombers just close enough to reach Japan. Led by Col. Jimmy Doolittle, the B-25s successfully took off from the Hornet’s flight deck — something that was not guaranteed — and hit various targets in Japan, including the palace of Emperor Hirohito. The raid did little physical damage, but was a morale victory for the U.S.

Aviation historian John Fredrickson will talk about the B-25’s role and significance at noon. After that, two B-25 pilots will answer questions about the airplane before Grumpy’s 1 p.m. flight.

After the flight, rides will be available for members on three of Historic Flight Foundation’s aircraft: the B-25D, a North American Aviation T-6 trainer and a de Havilland Beaver.

The event is open to the public. Rides are available for members. Given the cost to keep the vintage planes in the air, the rides are not cheap: $150 for the Beaver, $495 for the B-25 and $600 for the T-6.

Flights also will be available May 20 for Paine Field Aviation Day.

Dan Catchpole: 425-339-3454; dcatchpole@heraldnet.com; Twitter: @dcatchpole.