The troubled airline industry has been beset by a host of problems on all sides as rising oil prices and a weakening U.S. economy have combined to take a big bite out of the carriers’ bottom lines. At the same time, efforts to increase cost efficiencies through mergers have been blocked by labor unions.

Airlines looked like they were battling back from a five-year slump following the 9/11 terrorist attacks, a period in which carriers rolled up $35 billion in losses. But while demand for air travel remains high, passenger satisfaction is at a historic low. Operational performance, which includes everything from on-time arrival to lost luggage, is at its lowest point in 20 years, according to the latest Airline Quality Rating study. “With the U.S. airline industry at rock-bottom in terms of overall performance, greater accountability is necessary,” said Brent Bowen, a researcher on the study who’s with the University of Nebraska at Omaha.

Airlines are searching for ways to cut costs without adding to the already unpopular passenger charges and fees, especially as consumer spending wanes. Fuel is the biggest expense category for airlines, and with oil north of $100 a barrel and heading higher, consolidating to capitalize on economies of scale seems to make sense.

Although a number of deals have been proposed, none have really been able to get off the ground.

Stalled U.S. Airline Merger

Delta Air Lines Inc. (DAL) and Northwest Airlines Corp. (NWA) have been in merger talks for months now. Several important issues have already been decided. The combined carrier will fly under the Delta name and will be based in Delta’s home city of Atlanta.

Delta Chief Executive Officer Richard H. Anderson will remain on as head. But the stumbling block in a deal that would create the largest domestic carrier is the endorsement of the pilots.

In the past, airlines have had the pilots hammer out a deal after a contract has been signed. But hoping to have a fully functional combined airline that much sooner, Delta and Northwest encouraged their pilots to negotiate as soon as the planned merger was announced.

Unfortunately, the extra time hasn’t helped. The two unions have been unable to come to an agreement on seniority, which affects pay as well as route selection and the types of aircraft flown for the 12,000 pilots involved in the merger.

Without an agreement, the two unions have refused to endorse the merger.

Labor union support is critical to any merger, as Delta’s pilots’ union was instrumental in derailing a hostile bid takeover by U.S. Airways Group Inc. (LCC). But without the merger, Delta and Northwest will be forced to implement other cost-saving measures, including raising fees and cutting jobs.

UAL Corp.’s (UAUA) United Airlines and Continental Airlines Inc. (CAL) had also started merger talks earlier this year, but negotiations are on pause as the two airlines are waiting to see what happens with Delta and Northwest, a source with knowledge of the matter told Reuters.

European Merger Woes

Meanwhile, across the pond, Franco-Dutch carrier Air France-KLM (OTC: AFLYY) is facing similar labor opposition to its buyout of Italian carrier Alitalia – Linee Aeree Italiane S.p A.

Alitalia recently suspended trading of its shares and is estimated to be losing almost $1.5 million (the equivalent of 1.0 million euro) a day. The struggling carrier desperately needs the merger to go through in order to survive. Without a much-needed capital infusion from Air France-KLM, the carrier will undoubtedly have to file for bankruptcy protection.

But unions failed to approve the Air France-KLM bid, which included a 10% staff reduction, a $1 billion capital infusion and an all-stock bid that valued Alitalia at $217.7 million (138 million euros).

Air France-KLM said on Monday this was “the only plan able to allow Alitalia to return to health swiftly,” Reuters reported.

The Italian government is eager to divest its share of the financially unsound airline and Economy Minister Tommaso Padoa-Schioppa, the driving force behind the sale, has said unions must make a move fast or risk having the government appoint a special administrator to take over the negotiations.

With Italy’s elections looming on April 13 and 14, the government is eager to find a favorable solution.