Before the start of trading this morning, AMR Corporation (AMR) reported fourth-quarter earnings. The company lost 77 cents per share on an adjusted basis, 2 cents worse than analysts had expected. The miss sent shares of the stock lower.

Though earnings were disappointing, there were two positives in the report. First, mainline load factor was 78.3%, the third highest it has ever been during the fourth quarter. (Load factor measures how full a plane is.) Second, revenue per seat mile rose 5.5%.

As a result, brokerage analysts have boosted their fiscal 2009 earnings estimates on 13 airline holding companies during the past few weeks.

The positive changes have resulted in a 4-week revisions ratio of 1.59 for Transportation-Airlines.

To put the group's revisions ratio in perspective, just 13 industry groups have a revisions ratio above 1.0; 189 industry groups have a revisions ratio of 0.99 or lower.

(The revisions ratio is the number of positive revisions made to earnings estimates over the past 4 weeks divided by the number of negative revisions. Ratios above 1.0 means brokerage analysts have become optimistic. Ratios below 1.0 means analysts have become pessimistic.)

Cheap Oil and Higher Fees

Low oil prices have been a big help to the airlines. Fuel is a significant variable cost and the longer crude stays in its current range, the better airline margins will look.

It should also be noted that brokerage analysts were behind the curve in predicting how high crude would rise and how low it would fall. Now, with crude oil remaining cheaper than most thought, brokerage analysts are adjusting their 2009 average fuel price projections. As a result, they are increasing their full-year profit projections.

At the same time, carriers have not removed the fees they instituted last year. According to Bestfares.com, most airlines charge $15 for the first checked bag and $25 for the second. Not only do these fees bring in extra revenues, they practically go straight to the bottom line.

Load Factor Continues To Rise

The other factor that is helping the airlines is the load factor. The load factor is a measurement for how full the plane is. Much to the chagrin of travelers, load factors continue to rise.

The continued focus on fewer flights and more crowded planes is helping to offset the overall decline in travelers. By reducing capacity, airlines are better able to improve margins.

It may sound odd to say that cutting back on business is a positive, but fewer flights means less labor and fuel costs. Since the amount of labor or fuel is not proportionate to how crowded a plane is, fewer but more crowded flights helps profitability.

Airlines With Positive Revisions

There are 9 companies within Transportation-Airlines with recent positive earnings estimate revisions from 4 or more brokerage analysts. Included in this group are Zacks #1 Rank ("strong buy") stocks Allegiant Travel Company (ALGT) and US Airways Group, Inc. (LCC). Also receiving multiple positive revisions are 7 Zacks #2 Rank ("buy") stocks including JetBlue Airways Corporation (JBLU).

Related ETFs

There is no ETF solely focused on the airlines. The closest is the Dow Jones Transportation iShares (IYT). This fund also holds railroads, trucking companies, freight companies and shippers.

Zacks Premium and Zacks Elite subscribers can view the Zacks Industry Rank List at http://www.zacks.com/zrank/zrank_inds.php. This interactive list allows you to see all of the companies, and their Zacks Rank, within more than 200 industries. Shown below is the Zacks Sector Rank List, which shows the trend in estimate revisions on a broader scale.

Charles Rotblut, CFA, is the senior market analyst for Zacks.com. He can be reached at crotblut@zacks.com.