Priceline has rode overseas growth to become the best positioned online travel agency in the group, evidenced by a 65 percent increase in international bookings that helped pad strong 2011 first quarter profits.

FORBES: Playing The Fire In Priceline Without Getting Burned

Nevertheless air tickets bookings draw traffic and account for over two-thirds of online bookings overall, which necessitates their presence at any online travel agency especially for those that offer packaged deals or discounts for group travel.

FORBES: Airline Tickets Only Contribute 2% To Priceline Stock Price