Flies are attracted to laptop computers. I know this because I am writing from a sweaty departure lounge at San Jose in Costa Rica. At least the swarm of insects reading this screen has got off the ground, which is more than American Airlines flight 2152, destination Miami, can boast.

The departure board predicts an "8.50am On Time" take-off with a confidence that is doubly annoying since it is now almost 11am. The screens are promising an 11.01am departure, which would take a miracle of organisation - something that the airline has not so far demonstrated. My boarding pass, meanwhile, asserts 11.04am.

In one sense the delay has been welcome: the queue for check-in was so long that I reached the desk long after the flight should have departed. Our numbers have swelled with passengers from the Dallas flight, which has been cancelled. All of us have been at the airport for four hours or more. We have been given nothing: no explanation, no breakfast, not even a cup of Costa Rican coffee.

The reason for describing this sorry scene is not simply to whinge (though with every passing minute and subsequent missed connection at Miami, the collective grump is deepening ). It is to ponder the effects of the proposed alliance between British Airways and American Airlines. In terms of customer service, most British carriers are far superior to their US counterparts. But if a link is made between BA and AA, then service levels will need to find a common denominator. And given that American is twice the size of its putative partner, I doubt whether BA's standards will prevail. Big is not always best: before the collapse of the USSR, Aeroflot was the world's largest airline.

The flies, meanwhile, are buzzing in agreement.

Passenger power helped bring down an airline this week, when Excalibur Airways went into receivership. Twice in the past fortnight, passengers travelling on the airline's DC-10 service between Manchester to Florida refused to board the aircraft, claiming it was unsafe. They demanded to be flown by another airline, and Excalibur acquiesced.

Some reports at the time said "smoke from the air-conditioning system entered the cabin". If smoke had been in the cabin, the aircraft would have been grounded; I assume the substance was merely condensation of the sort that gives passengers on Ilyushin aircraft a regular drenching.

Since the company collapsed, all the passengers booked on its flights will find themselves travelling on other airlines whether they like it or not. Yet the people who insisted on switching from the Excalibur flights were, I suggest, misguided. That take-off should have been postponed repeatedly shows how seriously safety is taken by British airlines. In other parts of the world, the faults might have been ignored.

Furthermore, the fact that DC-10s have a less than perfect safety record is all the more reason to fly in them. It is sadly the case that plane crashes make flying safer - by analysing accidents, manufacturers and aviation authorities can take steps to prevent repetition of a tragedy.

The notion that passengers should presume to know better than the pilot is a dangerous one. Thankfully, we have yet to experience the sort of extortion prevalent a few years ago in parts of the Far East. Passengers on delayed flights would refuse to disembark until they received cash compensation for the late arrival. But if airlines cave in to hysteria, they will only have themselves to blame if the public seeks to profit from problems.