TOPEKA, KAN., SEPT. 6 -- President Bush got to have his cake and eat it today -- savoring the new luxurious Air Force One while aides pointed out he had nothing to do with the multimillion-dollar pricetag that paid for extras such as the 85 telephones, the seven bathrooms, the built-in movie screens or private office, changing room and presidential medical suite.

Bush, a World War II naval aviator who seems never to have heard of a plane trip he didn't want to be on, pronounced the converted jumbo Boeing 747 "great" before settling in, presidential slippers parked beneath the new presidential bed, for the jet's maiden trip from Washington to Topeka today.

He reminded reporters twice that Congress had approved the purchase of the plane in 1986 and that not he but his predecessor, Ronald Reagan, had planned its amenities. "Thank heavens somebody else did okay for me five years ago," Bush said.

For $410 million -- the cost to the taxpayers of the plane, an identical backup and a new hangar -- Bush got what probably will be a major advantage for him: the ability to fly 1,400 more miles without refueling stops than the previous Air Force One, a 20-year-old Boeing 707, could. The plane can also be refueled in the air, but officials said that would be done only in an emergency.

Then there are the amenities Bush had to live without before today, like the shower in the presidential suite that also includes the lounge with two roomy fold-out beds, a dressing room, a private office and a conference/dining room. The shower, it turns out, was tested by White House director of administration Bonnie Newman to make sure that when the president turns the spigot, something like hot water comes out.

"It was a kick," she said, to be the shower guinea pig.

This is a plane that reflects the president it was made for: Reagan. Video monitors sprout everywhere; projectors and screens make movies and other visuals easy, and the decor could be called Californian. The Bushes' lounge is decorated in browns, rusts and beiges and features a wall mural that looks like the California sky at sunset.

For Bush, the plane will be as good as the White House for his favorite pastime -- telephoning. The Air Force says the 85 phones offer "state-of-the-art mission communications systems" that will provide "worldwide clear and secure voice and datacommunications."

One of the White House physicians, Larry Mohr, gave reporters a tour today of another major new feature -- the medical unit equipped for use as an emergency operating room. It has an operating table that folds out of the wall, all the latest emergency monitoring and other equipment, and even looks like a doctor's office. The magazines on the table of this office, however, are recent.

Before the new plane made its debut, emergency blood was carried in an ice chest. This plane has a refrigeration unit for that purpose. Naval medical ships

had previously been stationed near a traveling president when he was out of range of a U.S. hospital. With the new Air Force One, that won't be necessary, Mohr said.

The plane has a roomier, better-equipped section for reporters, but the Air Force stewards are the same. They quickly admonished reporters to keep their feet off the furniture. "We're trying to keep it nice in here," one said.

White House Chief of Staff John H. Sununu told reporters, apparently in jest, "We did ask for piranhas back in the sinks in the press area."

This plane can carry more people, feed more people and fly farther than the old model, all advantages for a chief executive who has thus far visited 40 countries and 17 states, a record.

This was the plane that was to have taken Ronald Reagan home to California when his presidency ended, but two years' worth of delays prevented that. A major cause of the delay, Boeing officials have said, was equipping the plane with wiring that can withstand the effects of a nuclear blast. It also is equipped with an anti-missile system and other special defensive features.

Boeing agreed to deliver this plane, plus the backup, for $262 million under a $410 million fixed-price contract, and as actual costs rose Boeing absorbed most of the extra. The huge,

new hangar was built at the edge of Andrews Air Force Base field to accommodate the strikingly larger aircraft. Like its predecessors, it carries the same sky-blue, dark-blue and white coloring, with the words "United States of America" on its side and an American flag painted on its tail.

The words Air Force One do not appear. That designation belongs not to an individual plane but to whichever plane the president is traveling in.