RALEIGH, N.C. — It's a little unusual -- the heavy equipment rumbling past the control tower at

Raleigh-Durham International Airport

. But, get used to it.

There's at least four years of construction work to do at RDU, and that's just on Terminal C.

Plans for Terminal C show what a $350 million investment is expected to produce: a more modern and more passenger-friendly terminal with much more space.

RDU hopes its upgrade will rival the recent renovation of Southwest Florida International in Fort Myers.

Some frequent fliers who saw the plans said RDU is overdue for an upgrade.

"Right now, we do need to modernize, especially at Terminal C. Terminal A is pretty good at this point," Pano Paschaloudis said. "I think we need to get some more facilities -- for example, restaurants, pubs, stores and so forth. I'm stuck at the airport quite a bit."

The airport authority said all this construction work will have minimal impact on drivers and passengers.

"There will be minor inconveniences to passengers," RDU spokesperson Mindy Hamlin said. "We may see some roadway changes; we will communicate that to passengers, but there will be no major impact."

RDU began planning for a new terminal in the mid 1990s. The terrorist attacks on Sept. 11, 2001, put that on hold.

Now the idea is to build an airport that handles the Triangle's rapid growth and upholds the region's hi-tech reputation.

Once terminal C is complete in 2009, the plan is renovate terminal A.