by Leslie Goffe in New York

JetBlue is that rarest of things right now - a money-making airline.

While other American carriers are teetering on the brink of bankruptcy, this low cost carrier has exceeded Wall Street expectations by recording a net profit of more than $15m in the last quarter.

But some analysts say JetBlue is about to face its first real test now that two larger rivals, Delta and United, are preparing to muscle their way into the territory it has carved out for itself.

Competition increases

Since JetBlue began operating three years ago it has had little competition in the very profitable low cost airfares niche.

But that is about to change: two of the largest American airlines, United and Delta, will soon launch their own low cost carrier services.

Now they are trying to imitate us JetBlue CEO David Neeleman

They will be modelled on JetBlue, with individual in-flight satellite television, online reservations and of course, low fares.

United said its new service, temporarily codenamed 'Starfish', will be ready before the end of the year. And Song, Delta's alternative to JetBlue, will begin service on 15 April with a flight from New York City to West Palm Beach on the key Florida route.

Carbon copy

JetBlue's chief executive officer David Neeleman is concerned about the developments, but insists there is more than enough business in low cost fares to keep everyone happy.

"You know first of all it said it wouldn't work and now they are trying to imitate us," he said.

"If it works there's plenty of business for all of us. I guess what they are trying to do is protect what they have, because they have lost a lot of business.

We recognise that customers have become more jaded about flying Song president John Selvaggio

"Maybe by improving their product a little bit they'll get people to spend a few more bucks," he added.

Cheap deals

Song and JetBlue will go head-to-head in the lucrative Florida routes. And Song's ticket prices will be among the cheapest available, with domestic flights expected to sell between $79 and $299.

Song is able to cut prices in this way by pushing up production in every possible way.

For example, it will use just four flight attendants aboard a 200 seater plane rather than the usual five or six.

Its jets will fly longer and make more trips each day, and it will cut 30 minutes from the average time it takes to turn the 757s around in between trips.

We'll do whatever it takes, says Song president John Selvaggio, to fill planes and make price-conscious consumers happy.

Customer choice

"We recognize that customers have become somewhat more jaded about flying," he said.

"It is really a win for the customer and a win for the airline because there is tremendous growth in this business," he said.

Strategic routes

Analysts like Jamie Baker of JP Morgan in New York believe Song was created simply to squeeze JetBlue out of the lucrative Florida routes that it has made its own.

"I think what Song and Delta are hoping to do is slow the growth of JetBlue and other discounters," he said.

But only time will tell whether JetBlue's passengers will opt for the cheapest fare or stay with JetBlue come what may.