Economic worries are taking their toll on the number of high-flying corporate bosses hiring private planes, according to Gatwick-based charter brokers Air Partner.

The firm, which arranges planes for business magnates, companies, royalty and prime ministers, said "lack of confidence and activity" in the world's financial markets was affecting trade in the UK.

Shares dived 18 per cent on the announcement, falling 67.5p to 310p, as the group said the downturn was expected to significantly reduce its forecast profitability in the current financial year.

Managing director David Savile said one impact on business had been from fewer companies floating on stock markets - resulting in fewer planes ordered by firms keen to jet their chief executive and advisers around to woo investors.

He said: "If you are doing an IPO (initial public offering), you would travel by private jet because you need flexibility. Private jets can do an itinerary in less than half the time.

"People think they are horrendously expensive but, if you put them into context, they are not."

Suppose it is £20,000 to hire one - say if you are taking four working days of a chief executive's time, plus add in other costs such as advisers' fees, then a private jet is sometimes the small part."

Mr Savile stressed IPOs were just part of the company's business, accounting for less than 25 per cent of UK sales.

"We also undertake a lot of work for governments, royalty, industry and commerce," he said.

Following the current "small blip", Air Partners said it was hopeful of a rapid recovery in business once confidence returns.

The update came as the group showed pre-tax profits for the six months to January 31 had risen 38 per cent to £1.2million while turnover rose 42 per cent to £46.3million.

The group is in the process of expanding overseas and aims to open 20 more offices in the next five to ten years, building on its existing operations in Germany, France, Austria, Switzerland and the United States.

The ambitious launch of the world's biggest executive jet earlier this year has been an important step for the company.

The Boeing 747, which usually carries more than 400 people, was turned into a 106-seat luxury aircraft. It is targeted at major corporations, governments and other sectors of high-profile business and also at conference, event and incentive travel.

Heads of state are also among those expected to be attracted by the ultra-luxury of the new jet.