Delta Air Lines Inc. (DAL) said Thursday that it was one step closer to completing its merger with Northwest Airlines, which will create the world's largest air line by passenger traffic.

The two carriers received Federal Aviation Administration (FAA) authorization to operate as a single carrier. They can now fully combine flight numbers, schedules and ticketing under the Delta name. The air lines have already integrated many operating procedures, including the use common technical manuals.

What's holding the airline sector back, in addition to high jet fuel prices, and keeping the likes of AMR's (NYSE: AMR) American, Delta (NYSE: DAL), UAL's (NYSE: UAUA) United, Southwest (NYSE: LUV), and Continental Airlines (NYSE: CAL) from realizing their potential?

Many economists and analysts would agree that, along with other infrastructure and related investments, the nation's air traffic control system must be upgraded, if the United States seeks an air transportation system capable of maintaining a high level of safety -- and better service -- in the 21st century's more-crowded skies.

Further, that the United States has not already replaced an essentially generation-old air traffic control technology with a modern system is a serious demerit, and one that has -- through delays, cancellations, and other problems -- taken a toll on the flying public and the major carriers.

For anyone who has plans to fly on American Airlines, AMR Corp (NYSE: AMR) or Delta (NYSE: DAL) today, you may want to call ahead and verify that your flights are still taking off as planned, as both airlines are canceling hundreds of scheduled flights today.

Both carriers are grounding a large number of flights as they continue to hold inspections on wiring bundles on some of their planes. For American, the company is planning to ground 132 of its flights today, while Delta is canceling 275 flights.

The Federal Aviation Administration is in the middle of a massive inspection project, in which it stated that it will be inspecting 10 safety orders (also known as airworthiness directives) at every single major airline by March 28. This comes after a scandal broke out over missed inspections at Southwest Airlines (NYSE: LUV) earlier this year.

John F. Kennedy International Airport has long been a historic gateway to the United States, but in today's world, Alan Levin of USA Today called a recent visit "more like a dysfunctional parking lot."

Levin couldn't be closer to the truth. I live in Queens, New York, where not only JFK Airport resides but also LaGuardia International Airport on the northern side of the county. Both airports could be classified as "dysfunctional" during a slow day. Through May this year, about four in ten flights at JFK, LaGuardia and Newark were at least 15 minutes late, according to the federal Bureau of Transportation Statistics. JFK is on pace to handle 460,000 flights this year alone, 33% more than the turn of the century - and that's only seven years ago.