Simon Calder: Despite this disaster, low-cost flights remain a generally safe way to travel

The lower the fare, the higher the risk? After yesterday's crash in Greece involving a small, low-cost airline that question is bound to be raised by many. But the evidence from 35 years of no-frills flying suggests little correlation between cheap fares and fatal accidents. And even though yesterday's tragedy follows closely on the destruction of an Air France Airbus at Toronto, flying remains one of the safest of all human activities.

It is too early to speculate on whether cost-cutting contributed to the Helios Airways crash. Certainly, no-frills airlines seek to squeeze out cost wherever they can from their businesses; in an industry that is chronically unprofitable and increasingly competitive, cutting a pound or two in airport fees or inflight service can spell the difference between success and failure.

Some speculate that low-cost airlines must inevitably economise on safety - and that by paying a higher fare you must in some sense be buying a safer product. Yet the ValuJet disaster was a rare exception. "If you think safety is expensive", runs the unspoken mantra among the no-frills airlines, "try having an accident".

The giants of low-cost aviation in Europe, easyJet and Ryanair, have each flown about 100 million passengers since they began. Neither has suffered a fatal crash.

"Enormous amounts of money and manpower are invested in ensuring that we operate safer aircraft to safer airports with well-trained crews", says the greatest cost-cutter in the business, Michael O'Leary. Ryanair's chief executive says bluntly: "You don't have a business unless it's safe. Nobody would ever compromise on safety."

Even Ryanair's excellent record is eclipsed by Southwest Airlines, the original low-cost airline. Since its first flight in 1971, the Dallas-based carrier has flown over one billion passengers without incident.

"I wish I could bottle their secret and pass it around to everyone in the world," says Dr Todd Curtis, the aviation safety expert who runs the website. "They have a very solid operation, run by a very straightforward group of people." The only aircraft Southwest has ever operated is the Boeing 737, the type that crashed yesterday. It was the 55th 737 to be lost in a fatal accident, but that needs to be set against the number of safe missions accomplished; the 737 has flown more passenger flights than any other aircraft.

Next Monday marks 20 years since the last fatal crash involving a BA aircraft, coincidentally also a 737. The Boeing was accelerating along the runway at Manchester when fire broke out in one engine. It quickly spread to the fuselage, and 55 people died.