Showing up early, waiting in lines, going through arguably invasive searches. It's all a part of the process. But, the voice of passengers is growing louder. The federal Transportation Department is set to release its annual study of airline quality today, which reveals which airlines got the most complaints.

Complaints about airline services to the Transportation Department have increased by 28 percent in the last year. Here's a quick look at how the nation's 16 largest airlines ranked, based on number of complaints per 100,000 (list reflects most complaints to least complaints):

      -Delta Airlines, 2
      -United, 1.64
      -US Airways, 1.53
      -Continental, 1.48
      -American, 1.44
      -Comair, 1.25
      -JetBlue, 1.25
      -Frontier, 1.23
      -Hawaiian, 1.16
      -American Eagle, 1.03
      -AirTran, 0.90
      -Skywest, 0.61
      -Atlantic Southeast, 0.54
      -Mesa, 0.53
      -Alaska, 0.44
      -Southwest, 0.27


The study isn't all bad though, it shows that airlines did better at arriving on time, and getting both passengers and their luggage to the same destination.

The department is crediting more complaints to fewer, crowded flights as airlines try to match supply and demand.

The biggest category of complaints includes cancellations and delays.

Southwest Airlines has the lowest consumer complaint rate. Delta had the worst rate again.
Four of every five domestic flights arrived on time last year. Hawaiian Airlines was the best, at 92 percent. Comair, a regional airline, was last at 73 percent.
The rate of mishandled bags was the best in the two decades.

The ratings are based on statistics for airlines that carry at least 1 percent of the passengers who flew domestically last year.

Richmond International Airport doesn't carry Southwest, which was the highest ranked airline in the study.