Sea-Tac is nearly tied with Charlotte Douglas International, with on-time departures of 79.3 percent and on-time arrivals of 76 percent. The airport is served primarily by Alaska Airlines and its subsidiary Horizon Air, which recently announced that it is reducing the number of flights from Seattle to Portland and Bend, Ore., Idaho Falls, and Sun Valley, Idaho, among others, and is discontinuing service to Butte, Mont.

The number of passengers boarding planes at CLT increased three percent in April from the same month last year. The question is whether the increase will hold given that the airport is US Airways largest hub—the carrier recently announced it is reducing flight operations by 8 percent, and charging a $15 fee for each bag checked.

Located in northern Kentucky and servicing the greater Cincinnati area, CVG has seen a scaling back of the number of flight operations in recent years—in fact, there was a 7.6 percent drop in passenger movements from April 2007 to April 2008. Flying at or below capacity tends to improve punctuality—79.7 departed on time, and 76.4 arrived on schedule.

Located just outside of Washington D.C., the domestic hub is served primarily by US Airways, yet another major carrier that has recently announced will be slashing services (by 8 percent) by the end of the year. For the first five months of 2008, DCA's on-time arrivals are nearly 77 percent while punctual departures are 80.2 percent.

Orlando is one of 18 U.S. airports where passengers can use a Clear card, a pre-approved ID card that, for $128 per year, allows fliers to skip to the head of the security line (though passengers must still go through security). It's unknown yet whether the card is impacting efficiency at the terminals, but MCO had 79.4 percent on-time departures so far this year, while on-time arrivals are at 77 percent.

Nearly as busy as nearby Dulles in Washington D.C., BWI handles almost 21 million passengers per year. On-time arrivals are 78.5 percent; on-time departures are nearly 79 percent, making it the 10th most punctual airport in the nation

Climbing from 13th position last year to number nine for the first five months of 2008, Tampa International saw 80.5 percent of commercial flights take off on time, while 78.1 touched down on schedule.

Essentially tied with Phoenix Sky Harbor, SAN is the second most punctual hub in California. As for arrivals, 77 percent were on time; 81.8 percent of departures left the tarmac on time.

Recently given a perfect safety inspection rating by the FAA for the third consecutive year, the nation's eighth busiest airport saw 79.3 percent of commercial flights arrive on time for the first half of 2008, while 80.1 departed on schedule.

SJC is the smallest and the most efficient of the three airports serving the greater San Francisco area, but what else would you expect from an airport located in the heart of Silicon Valley? When it comes to timely departures, SJC saw 82 percent leave on time. As for arrivals, 79 percent of flights touched down according to schedule.

More than 50 percent of ABQ passengers are enplaned on Southwest flights—Southwest Airlines also happens to rank as the nation's most punctual large carrier. This, no doubt, has had an impact on the airport's on-time performance.

The nation's 15th-busiest airport, and the second busiest in the Rockies (behind Denver International), SLC moved more than 22 million passengers in 2007. Its on-time departures for the first five months of 2008 are 82.6 percent; timely arrivals hover at 79.7 percent.

Over a 12-month period ending in April, PDX moved 4.5 million passengers, which represents a five percent increase from the year before. Despite the growth, the airport still maintains 83.9 percent on-time departures, and 79.6 percent on-time arrivals, giving it a cumulative score of 81.8 percent.

Even though regional carriers Aloha and ATA went out of business recently, and visits to the island of Maui (where Kahului is located) were down nearly 10 percent in April, these changes haven't greatly impacted Kahului's ranking as the nation's second most punctual airport. In fact, its on-time performance actually slipped a little since 2007, when it was ranked first place. But it still boasts an impressive on-time performance rate of 84.2 percent.

The primary gateway to Hawaii from points around the world, HNL is serviced by the nation's most punctual carrier, Hawaiian Airlines. Uncongested airspace and sunny skies have no doubt had a positive effect its on-time arrival rate of 83.7 percent; departures, 84.9 percent—making it the most punctual airport in the United States.