WASHINGTON -- Congress plans to spend $550 million to buy eight jets, a substantial upgrade to the fleet used by federal officials at a time when lawmakers have criticized the use of corporate jets by companies receiving taxpayer funds.

The purchases will help accommodate growing travel demand by congressional officials. The planes augment a fleet of about two dozen passenger jets maintained by the Air Force for lawmakers, administration officials and military chiefs to fly on government trips in the U.S. and abroad.

The...