FOR the first time ever, the price of a business-class return ticket to New York has fallen below pounds 600. The standard fare is pounds 2,164, but Air India will take you from Heathrow to JFK and back in the upper deck of a Boeing 747-400 for about a quarter of that amount. The Travel Bug (071-835 2000) is selling tickets for pounds 589 on the carrier's daily flights, for outbound travel by the end of October. The regular first-class fare of pounds 3,948 is also reduced by 75 per cent.