I suggest federal employees be allowed to arrange their own airfare, like they're able to do for hotel reservations.
After booking tickets for a recent conference, I was frustrated by the fact that the tickets I purchased through the government travel agent (ADTRAV) were about 25% more than what I could get if I booked a similar itinerary myself through either airline websites, or fare aggregators (e.g. kayak.com). I've gotten in trouble in the past for booking non-refundable travel on my personal credit card, which was > $100 cheaper per ticket.
The Bureau of Labor Statistics says there are 2 million civilian employees. If each employee could save 20% by price shopping themselves, and each employee travels twice a year (averages $400 RT airfare), we could be potentially saving more than 320 million dollars per year (2 million * 0.2 * 800)