ACCOUNTS manager Soon Lishan, 26, was scheduled to return home after a week-long holiday in Hanoi but she was stalled by an unforeseen hiccup.

At the airport, staff from budget carrier Tiger Airways told her and other passengers that their flight had been cancelled due to a mechanical fault with the aircraft.

She had little choice but to wait as there was only one flight to and from Hanoi a day. Twelve hours later, the problem was finally fixed and the plane took off.

"The airline gave us a free flight of equivalent value out of 'goodwill'. Still, the delay definitely put a dampener on my holiday," she recalls, adding that she paid about $300 - including taxes - for a return ticket.

Indeed, paying low prices for air travel may seem like a boon to penny-pinching travellers, but flying low-cost may also lead to a slew of inconveniences.

A disadvantage of going budget, like in Ms Soon's case, is the limited flight schedule: Miss a plane and the next one may only be the day after.

On the other hand, a premium carrier with a bigger fleet may be able to quickly reassign its passengers to the next available flight on the same day.

Aviation experts interviewed by The Straits Times said that in general, consumers should be aware that low-cost carriers - or LCCs - play by different rules.

Mr Jason Pereira, an associate at travel and leisure research consultancy Globalysis, said: "LCCs tend to offer low ticket fares on flights while removing many of the traditional luxuries and conveniences premium flights offer."

So don't expect many creature comforts for bottom dollar.

Budget carriers typically adopt a one-class-fits-all approach to cabin seating - usually economy class for all.

Mr Richard Pinkham, aviation analyst at the Centre for Asia Pacific Aviation, said the airline may try to install more seats - resulting in less leg room.

Comparing the same Airbus A320 aircraft used by SilkAir and Jetstar Asia, he notes that the former has 142 seats while the latter has 180. The difference, he adds, equates to "21 per cent more real estate" for the airline.

Other frills eliminated may include meals, cushy waiting lounges, aerobridges that take you directly from the plane into the airport terminal, printed tickets or boarding passes, and 'frequent flyer' loyalty benefits.

"On an LCC, the passenger pays for only what he needs," says Mr Mario Hardy, vice-president for Asia Pacific at travel intelligence company OAG Worldwide. "For cost-sensitive passengers, this is a good alternative. And frankly, on short-haul flights, do you really need a full meal?"
Perhaps a bigger concern of savvy travellers is connectivity.

Premium carriers may schedule their more popular flights to arrive at aviation hubs during the same window, usually the evening peak period, to make connections easier for passengers en route to another destination.

But LCCs are merely 'point-to-point' carriers who may choose to fly during off-peak periods, meaning you may land at a stopover with hours to kill before your next flight.

"They fly direct, drop you off and that's it," said Assistant Professor Terence Fan, who studies the LCC market at the Singapore Management University.

Another factor to consider is the possibility of delay resulting from multiple turnarounds, a problem that is admittedly not exclusive to LCCs.

But as Mr Prithpal Singh, a pilot and tourism consultant, explained, LCCs maximise the use of their aircraft by aiming for the quickest turnarounds.

"For larger scheduled airlines, the turnaround time at airport stops is between 60 and 90 minutes. For most LCCs, it's about 30 minutes. Any delay at any one or two stops will often affect other flights."

For peace of mind, check the airline's On Time Performance. Most reputable LCCs publish such statistics on their websites. For example, AirAsia's record shows that it was punctual 89 per cent of the time in October.

But check where you land and take off from too. Mr Pereira points out that most LCCs fly to secondary airports to reduce costs.

"These airports could be inconvenient to commute from and could sometimes cost more than the actual flight."
And what of safety? The issue has come under scrutiny since a high-profile air crash in September involving Thai budget carrier One-Two-Go.

Aviation experts, however, say it is a misconception that budget carriers use rickety, second-hand planes.

Most prefer using modern aircraft for the simple reason of fuel economy.

OAG's Mr Hardy said: "Overall, LCCs have the youngest in-service fleets."

As for who is in the cockpit, pilots flying a particular aircraft type all require minimum training and experience, said Mr Singh.

He added that LCC pilots who fly short sectors take off and land more often, chalking up more experience than their long-haul counterparts.

Ultimately, travellers should do enough research to make an informed decision about whom to fly with.

Mr Pereira advised: "A simple check on Google or Yahoo with the airline's name and 'accident' would probably show up past events if there were any."

"A number of LCCs are established in name or are subsidiaries of legacy airlines. These, like AirAsia, Tiger Airways, Jetstar Asia and Nok Air, are more likely to operate flights at very high safety levels."