WASHINGTON -- As Boeing lobbied against a rival aerospace company to win a $35 billion government contract, its activities included a curious donation: $10,000 to the Johnstown, Pa., Symphony Orchestra.

The orchestra was a favorite cause of Rep. John Murtha, the late Pennsylvania Democrat who, as a gatekeeper for the Defense Department's budget, held a lot of influence over Pentagon contracting.

Boeing ultimately won the contract to build a new military refueling tanker, after the company and its competitor donated to organizations held in favor by key Pentagon generals and lawmakers like Murtha.

The payments were disclosed under a 2007 law that opened a window into more than $50 million in previously hidden spending by lobbyists and their clients, according to a compilation by the nonprofit Sunlight Foundation. Most money spent in 2009 and 2010 went to nonprofit groups that were connected to government officials or honored them. For companies seeking influence, "it's a win-win," said Wright Andrews, a lobbyist and board member of American League of Lobbyists. "Give to charities and get a tax deduction."

"There's no question it gives you better access. Access is power. It goes to having a direct impact on whether you get support or not," Andrews said.

Boeing, while vying for the tanker deal that was among the largest government contracts, donated to groups that honored, among others, Senate Armed Services Committee Chairman Carl Levin, D-Mich.; Rep. Norm Dicks, D-Wash., then chairman of the Defense Appropriations subcommittee; Marine Gen. James Mattis, currently head of the U.S. Central Command; and Gen. David Petraeus, the incoming CIA director.