With more passengers pouring in and out of Ronald Reagan Washington National Airport than in past years, airports officials are looking to make millions of dollars in upgrades to keep up with the demand.

The domestic airport has seen about 4.4 percent more passengers in the last year even as the number of domestic flights nationwide remained stagnant, reported Metropolitan Washington Airports Authority President and CEO Jack Potter at a meeting last week. Reagan had 18.8 million passengers in 2011.

"Reagan is at a record level of activity," Potter said. "We're going to have to spend money to accommodate the growth."

Airport officials said Reagan is growing because the federal government has increased the number of flights allowed to come into the airport, and low-cost airlines like JetBlue Airways and AirTran Airways are offering more flights from Reagan -- popular options for passengers who want cheaper tickets and who want to be able to take the Metro to the airport.

But the growth has led to big problems for Reagan, from long security lines to full parking garages to not enough room for planes to park.

Economy parking spaces have been full for 61 days so far in 2012 -- equalling about 25 percent of the time, twice the frequency of parking garage closures in 2011, officials said.

Lines for passenger security checkpoints are often backed up in the early morning and midafternoon, MWAA said.

And on a steamy July day this year, a plane's wheels melted dents into an asphalt surface when it was forced to park there because the airport didn't have enough spaces with reinforced concrete. Officials have now fixed that by having planes park on steel plates, they said.

But the airport still needs long-term solutions, Potter warned.

"We're not satisfied with customer experience, and we want passengers to know we're reacting," Potter said.

The airport has a $45 million upgrade planned for its oldest section, Terminal A, with construction slated to start by the end of the year, including a wider security checkpoint, more baggage-handling areas, updated ticket counters and even better bathrooms. The authority expects the project to be done by the end of 2013, said MWAA spokesman David Mould.

And airports officials are studying further improvements for the airport, such as more parking spaces, but have yet to determine a price tag or funding, which could fall to the airlines to supply if the federal government doesn't give more to the airports, Potter said.