There is nothing about the three dozen paragraphs buried deep in a $34.6 billion spending bill approved by the U.S. Senate this week that would lead one to believe they were fought over for three years or that the final days before compromise were full of acrimonious sessions behind closed doors.

But the stakes were high in the battle over how many planes should be allowed to fly in and out of Reagan National Airport, and where those flights should go.

For the airlines and the senators who supported them, it was about passenger convenience and making money on lucrative new flights. For Northern Virginia and the senators who rose to its defense, it was about preserving the status quo and protecting a huge investment in the region's economic future.

The Senate bill says five new round-trip flights can be added at National and the routes for seven existing flights can be extended to the far reaches of the country. The House is working on a slightly different bill, so further compromise is in the offing.

It is overstatement to say that the multiyear funding reauthorization for the Federal Aviation Administration was held up solely by the National Airport issue, but it was on the shortlist of reasons the legislation stalled.

The competing parties have had clearly defined interests, but to understand them fully requires a bit of background.

National Airport, bounded by the Potomac River on one side and the George Washington Parkway on the other, has had nowhere to grow. Acknowledging that, the federal government began building an airport in 1958 in what were then wide-open spaces near Chantilly. It opened as Dulles International Airport in 1962.

To encourage people to use Dulles, and to recoup the cost of building it, federal authorities restricted the number of flights that could use National and the distance those planes could travel. Later, when a generation of jumbo jets came along, they were not allowed at National.

For members of Congress from Western states, that meant a trip to Dulles or taking a connecting flight from National when they wanted to fly home for the weekend. They also sympathized with airlines who wanted to provide direct flights from National to the West Coast.

Led by Sen. Jon Kyl (R-Ariz.) and Sen. Maria Cantwell (D-Wash.), they began the negotiations with a request for 75 new round-trip flights out of National, many to destinations beyond the traditional perimeter that limits most flights to within 1,250 miles of the airport.

Virginia's two senators, Democrats Mark R. Warner and Jim Webb, sought to derail that proposal.

Although the issue is often framed by Alexandria and Arlington County residents' objections to noise and air pollution, the Virginia senators felt there was a far more serious issue.

"The development of the Dulles Technology Corridor is driven in no small part by its proximity to Dulles and the international access the airport provides," Warner said. "Dramatic changes to flight rules at Reagan National could have a profound impact on traffic, flight operations and improvements currently underway at Dulles, on the airport authority's bonding ability, and on the region's economy as a whole."

Webb added: "This compromise preserves the careful balance among the area's airports and serves the broader economic interests of the region."

The region has invested billions in developing Dulles as a transportation and employment hub. The 23-mile rail line being built from the East Falls Church Metro station to Dulles and farther into Loudoun County may cost as much as $6.75 billion alone.

"When more long-haul flights come to National, the D.C.-bound passengers will fly there and only the people who are flying on to Europe and elsewhere will use Dulles," said one Senate staff member, describing an argument he heard voiced in closed-door negotiations. "That would create the possibility of half-full, money-losing flights coming into Dulles. That could jeopardize Dulles as a travel hub and jeopardize the federal investment in Dulles."

Over the past decade, exemptions from the perimeter rule have been made to allow 24 flights to Los Angeles, Phoenix, Seattle, Las Vegas, Denver and Salt Lake City. Under the current Senate compromise, seven shorter flights could be swapped for longer flights and five new round trips could be added. Once an impact study on the additions is complete, four more flights may be authorized.

"We reached a suitable compromise that will allow for greater access to Western states while not overburdening this region's airport system," Warner said.

The House bill would allow five new round-trip flights but has no provision to allow the conversion of existing flights to serve more-distant destinations.

Once a congressional compromise is reached, the U.S. Department of Transportation will put the new openings out for competitive bids by air carriers.

The use of wide-body jets would not be permitted for the new flights. National averaged 726 daily commercial flights in 2010.