The top 10 largest airlines, which account for 76.1% of all domestic air travel, lost a reported $145 million in Q4 of 2012, a significant improvement from the prior year's net loss of $602 million, the U.S. Department of Transportation's Bureau of Transportation Statistics (BTS) reported this week.

For the year, the top airlines earned a combined net income of $201 million, compared to a net income loss of $0.50 million in 2011.

American Airlines (UNKNOWN:AAMRQ.DL) led the way in the fourth quarter of 2012, reporting net income of $270.8 million, followed by Southwest Airlines (NYSE:LUV), which earned $78.3 million. For the year, Delta (NYSE:DAL) topped the list of large airlines, with $1.18 billion in net income, according to the BTS.

For 2012, the 10 biggest airlines generated a total of $159.5 billion in revenues, of which $3.5 billion were baggage fees and nearly $2.6 billion came from reservation change fees. Baggage fees in 2011 totaled $3.36 billion while reservation cancellation/change fees in 2011 were $2.38 billion.

In both the fourth quarter of 2012 and for the year, Delta earned the most in baggage fees, generating $203.05 million and $865.88 million, respectively. Delta also generated the most reservation change fees of the group, earning $184.67 million in Q4, and $778.4 million for the year.