The outlook was further muddied last week when it became public that US Airways was considering reducing its hub role in Las Vegas. Although some aviation analysts have suggested that Las Vegans shouldn't fret since the city is too great a destination for airlines to ignore, it just doesn't bode well that airlines are pulling back capacity at a time when the resorts need them to consider more flights. It may not be crucial for 2008, but when Encore, CityCenter, Echelon and Fontainebleau come on line, the resort community would prefer the airport be busier than it is today instead of working to catch up to where capacity once was.

US Airways' flight reduction could be troublesome because it is the second-busiest carrier operating at McCarran International Airport.

Las Vegans have always looked at US Airways and its predecessor, America West Airlines, as one of the airport's greatest assets. Although Southwest Airlines has a larger presence, US Airways was always viewed as one of the big guys in the industry that actually paid attention to what Las Vegas has to offer the world.

Many of US Airways planes are bigger than Southwest's. The airline flew to more cities than Southwest. It took note of Las Vegas being a 24-hour city and built a business plan that took advantage of that.

America West started the "night hub" concept for Las Vegas, and it was brilliant. Most of the nation's airports operate during daylight hours, and operations scale back when the sun goes down. But for America West and, eventually, US Airways, gate agents were just getting warmed up at 9 p.m.

For years, the airline would fly its nationwide routes, using Phoenix's Sky Harbor Airport as a transit point for passengers flying to their destinations. A group of flights would come in around the same time, park, let their passengers change planes and they'd be off to their next destination. When most carriers parked their planes for the night, America West and US Airways would use the same transit system it was using in Phoenix in Las Vegas.

A hidden advantage was that some tourists would take advantage of the night flights and arrive on the red-eye Friday night and fly home at 1 on Monday morning. Businesspeople also liked the idea because they could hop aboard an eastbound plane at 1 in the morning and arrive in time for a day of work and still get home that night.

McCarran has always been hopping Friday nights with tourists coming in for a weekend getaway and taking advantage of the fact that taxis and shuttle buses would be available, and the casinos and clubs would be full of action in the wee hours.

To make it worth their while, the airline would knock a few bucks off the ticket price so that the planes would be full.

That model worked when gasoline was $1.50 a gallon, but it doesn't anymore. Now, the airline has to charge more than it ever did to make a profit. When the planes didn't fill up, it became clear that US Airways was better off parking its planes instead of making the late-night trips to Las Vegas.

So what happens next?

US Airways appears to be in full pre-merger mode. United is the partner. Everything US Airways does is by the book so that the Securities and Exchange Commission won't see any shareholders taking advantage of insider information.

But there are a number of baffling elements to the proposed US Airways-United merger and some of them affect Las Vegas and operations at McCarran.

First and foremost: Who's driving this train? US Airways Chief Executive Doug Parker has been one of the aviation industry's strongest advocates for consolidation. For years, he has contended that airlines would face financial struggles until capacity is reduced. And, for the most part, he's been right.

When he led America West's effort to acquire US Airways, it was regarded as one of the industry's best transitions, and it profited the airline almost immediately. To be sure, there were - and still are - some bugs in the America West-US Airways merger. Pilots and flight attendants from their respective former airlines still aren't on the same operational page and the feuds have resulted in lots of high-profile bickering.

Still, Parker presses on, doing what he thinks is in the best interests of his shareholders and his employees.

United, meanwhile, has stumbled through a series of initiatives, cutting employee salaries at almost every turn. It had a branding effort that was widely regarded as a failure, the airline's Ted brand. Ted eliminated first-class seating, promised low-cost fares, then delivered ticket prices that were higher than most of their competitors'.

The elimination of first-class seats was a particularly big deal for Las Vegas since United designated all flights coming into McCarran as Ted flights. That meant that high rollers from the East Coast or overseas - the ones who pay the most and are considered the airline's best customers - had no choice but to fly into Las Vegas on smaller planes with no first-class amenities.

United also has had some unusual staffing in Las Vegas. For years, United has had 39 or fewer daily flights to McCarran. When I asked local employees why that was, I was told that the union contract designated a change in pay scale and benefits at the level of 40 daily flights. United management has never confirmed or denied that, but that seems to make sense if the airline never goes beyond 39 daily flights.

So what would happen in a merger? Eventually, there may be some information that leaks out about the details of the deal, but it's hard to imagine an aviation industry without United Airlines or Doug Parker.

Would US Airways be the leader and then take United's name as was orchestrated in the America West-US Airways deal? Where would this "United Airways" corporate headquarters be, sunny Phoenix - which breathed a sigh of relief when Parker announced that Phoenix, not Arlington, Va., would house US Airways' headquarters - or Chicago, which has been United's home for years and is the corporate home of Boeing?

What would happen with the two airlines' hubs? US Airways brings Phoenix, Philadelphia and Charlotte, N.C., to the table while United has Chicago, Denver, Washington's Dulles International Airport, Los Angeles International and San Francisco.

Most important to Las Vegans would be how McCarran is regarded. The potential elimination of US Airways' night hub operation aside, the airline has been pretty good for the city.

Currently, by McCarran's count, US Airways has about 101 daily flights on average. Incidentally, you might see the airline say they have 116 daily flights. That's because the airline and McCarran count flights differently. For example, if US Airways runs a flight Sunday through Friday, it considers that a daily flight. McCarran breaks down all the fractional amounts and comes up with an average that I would consider more accurate.

Meanwhile, United has - you guessed it - 39 daily flights. All of United's mainline flights go to the hub airports listed above with commuter partners offering a handful of flights to California. US Airways goes to 58 airports if you count those operated by its commuter partner, Mesa Air, which flies to Las Vegas under the US Airways Express and Air Midwest banners.

US Airways flew 1.9 million passengers to Las Vegas in the first quarter of 2008, a 22.3 percent decrease over last year, thanks primarily to a corresponding decline in capacity.

United flew 719,250 passengers in the quarter, down 8.8 percent from a year ago. The declines by US Airways and United have been the primary airlines responsible for McCarran's 0.5 percent quarterly decline in passengers to 11.28 million.

Although Clark County Aviation Director Randy Walker won't shed many tears about the loss of a US Airways hub - his mission is to bring in passengers that spend time and money in Las Vegas, not just change planes - he'll have a few logistical issues to address if United and US Airways tie the knot.

US Airways has filled nearly all of the A and B gates at McCarran. At night, when the airline gets busy, flights spill over into the C gates, where Southwest isn't as busy. United uses several D gates, which are on the verge of expanding. The airlines' counter spaces are relatively close to each other, but the gate transition would be something the airport would have to address.

There have been no indications when any announcement on a proposed merger would occur. But this is one that Las Vegans should pay attention to.

Although much of the aviation news has been bleak lately, there was a bright spot last week.

Las Vegas-based Allegiant Travel Co., parent company of Allegiant Air, reported first-quarter earnings of $9.7 million - not huge by industry standards, but anything in the black is a good thing.

Allegiant flew nearly a half-million passengers to Las Vegas in the first quarter and is creeping up on No. 6 Continental Airlines in the airport's passenger rankings.

Allegiant became the second airline to report a profit in the first quarter, the other being Southwest Airlines, the busiest carrier at McCarran and a company whose biggest operation is in Las Vegas.

Hmmm. The two airlines that carry a high percentage of leisure customers and have made Las Vegas a major presence in their business plan are the only ones that are profitable. Coincidence?