Charlie Shontz, an affable fellow from Louisville who likes to fly in his spare time, came to this English country airstrip for a friend back home who is a real estate developer. His friend's business must be booming because in the space of two hours or so yesterday, Shontz spent $100,000 on four aviation antiques, including a two-engined 1935 de Havilland DH90 Dragonfly.

Kermit Weeks is 29 and wears a dashing World War II-style leather flight jacket with the fur collar up. He is a member of a U.S. aerobatics team and thanks, he says, to some "investments, real estate, that sort of thing," he was able, with seeming casualness, to drop about $125,000 to buy a 1943 Hawker Tempest II that can't fly. He plans to put it in a Miami museum named after himself. The price, he reckons, was "a steal."

You might think that the size and price of these relics would drastically limit the number of customers eager to buy one. But well over a thousand people turned up here for the auction of about 50 of them organized by Christie's, the London fine-arts dealers. The normally quiet airstrip, home of the Imperial War Museum's own aircraft collection, logged in 200 private planes in the course of the morning.

In all, over a million dollars changed hands, including the highest price ever recorded for an antique aircraft. That was $390,000 for a 1943 Supermarine Spitfire LF Mk IXB, a legendary model that had its heyday in Royal Air Force dogfights with the Luftwaffe. Only 151 are left and few are as well preserved as this one. To prove it, a local pilot put the Spitfire through the equivalent of a test drive, performing some breathtaking skyborne paces as prospective owners marveled.

The seller was anonymous. The buyer was a syndicate fronted by a former RAF squadron leader and stunt flyer named Ray Hannah who said afterward he was prepared to pay even more. The syndicate plans to take the Spitfire to air shows, rent it out for period-piece movies and, presumably, give its new owners the thrill of flying it themselves.

Aside from a fondness for old planes, the crowd's other common feature appeared to be affluence. Many of the expectant faces under Christie's big tent as the bidding got under way had deep early-spring tans and if they were concerned about being away from jobs in the middle of the week, it didn't show.

A fair number were Americans. Shontz said he had combined his trip to the auction with some business--the purchase of wall paneling from a private library in London. He said it would be reinstalled in a Kentucky retirement village his friend is building, and naming Mayfair after the elegant London district.

Weeks is clearly a well-known figure in the world of antique flyers. After the sale, admirers clustered around to congratulate him on his successful bid. Weeks, who already owns 10 planes, said he is prepared to spend another $100,000 on the Tempest to make it airworthy.

Although British by nationality, "Colonel" Ian Willis is American in spirit. He is a member of the Confederate Air Force, a club of pilots with a taste for vintage aircraft. All its members, he explained, are called colonels, which for him was a big step up. During the war, he was a radio operator. Willis bid $27,500 for a 1930 Great Lakes 2T1A, but fell short of the minimum asking price.

The auctioneer was the Hon. Patrick Lindsay, the 54-year-old second son of the Earl of Crawford and Balcarres, a senior expert in Christie's old masters department and a collector himself of old aircraft and automobiles. Lindsay has a penchant for expensive gadgets. In one of his barns, The Times of London reported, he once kept an old steam engine in perfect working order for possible use as an emergency generator. Lindsay, silver-haired and in pin stripes, perched on a highchair and moved matters along with efficient flair and good humor.

A secret of successful auctioneering appears to be jollying things along. Whenever bidding stalled, Lindsay would mutter something that sounded final, bang his hammer and move on to the next item regardless of whether an acceptable price had been reached. Often it had not. "It's important to keep up the momentum," a colleague said. An atmosphere charged with the excitement of dueling bidders is a decided help.

For instance, as the price of the Spitfire bounded into the hundreds of thousands and then headed for a record, the tent went quiet. Hannah made the high offer and the crowd gasped. Down came Lindsay's gavel. Even the daredevils were impressed. CAPTION: Picture, This 1943 Spitfire fighter was auctioned off to a British syndicate for $390,000, a record price for an antique airplane. UPI