Just when you thought the major airlines should be heading down, they're going up. Despite the drop in crude oil prices since the beginning of this year, several of the major airlines announced Friday that they were increasing their fares.

The effort, which was led by American (NYSE:AMR), United, and Delta, would involve increases of as much as $5 on domestic flights. Northwest said it would raise its fares by $3 on trips of less than 1,000 miles and $5 for longer flights. Continental (NYSE:CAL) has not matched the increases. The fare increases coincided with a jet fuel price of $1.57 a gallon on Friday, well below summer highs of $2.25.

At the same time, both Delta and Northwest, much like two airplanes on the runway inching toward takeoff, moved forward with their respective reorganization plans. Delta, which has received a $10.4 billion buyout offer from US Airways (NYSE:LCC), asked the bankruptcy court late Friday to approve its disclosure statement to its reorganization plan. If the plan is approved at a hearing scheduled for Feb. 7, Delta could begin to line up votes to approve the plan. The airline is asking that April 9 be established as the voting deadline for the reorganization plan and that a confirmation hearing be set for April 25.

Delta's official unsecured creditors committee will be vital to the determination of whether the airline ultimately succumbs to US Air's offer or is able to emerge from bankruptcy as a stand-alone operation. The committee has been silent on its preferences since Delta received a sweetened offer from US Airways last Wednesday. This latest offer was predicated in part upon the Feb. 7 hearing being postponed and the creditors showing support for Delta's books being opened to US Airways.

Meanwhile, up in Minneapolis, Northwest filed its own 66-page bankruptcy plan Friday. The plan did not, however, address the major question surrounding the airline: whether it will merge with another carrier. While Northwest has hired an advisory firm, it has not commented publicly on its plans. According to a ruling by U.S. Bankruptcy judge Allan Gropper, Northwest will file more details of its reorganization by Feb. 15.

Under its reorganization plan, while Northwest's unsecured creditors would not have their claims satisfied in full, they would receive shares in the new company. As the airline has said throughout its bankruptcy process, current shareholders' shares would be cancelled and they would not be entitled to shares in the post-reorganization airline. Northwest's shares dropped $0.93 to $4.61 Friday.

It indeed seems that the airline industry is becoming bifurcated into the haves and the have-nots. As I told Fools last week, with fuel prices having turned favorable and cost-cutting beginning to come home to roost, I'd be inclined to look for investment opportunities in American, United, and Southwest (NYSE:LUV). In the other extreme, I frankly cannot predict the ultimate resolution of the current reorganization efforts at either Delta or Northwest. Were I a current shareholder of either carrier, however, I'd waste no time in lobbing a sell order to my trusty broker.

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Fool contributor David Lee Smith does not own shares in any of the companies mentioned. He welcomes your comments or questions.