Seeing the traffic can happen responses, I second the museum idea.

I have been there. maybe you can have b fast in the terminal. take the shuttle to the museum.

there are guided tours by volunteer docents. A Space Shuttle, SR 70' and several other aircraft.

Shop and cafeteria on site.

The Space Museum is fascinating displaying all sorts of aircraft from a very impressive spy plane to an old prop passenger plane. There is a cafeteria of sorts, very expensive, but a place to eat. This is definitely your best option. IAD has nothing of interest...very boring airport....and little more than four hours in DC would, in my view, not be worth the trouble. Hope it works out as you would like!

I didn't find the cafeteria to be that expensive... and even if it were, with free admission I don't mind subsidizing things a bit with (possibly overpriced) food.

Some of the volunteers are incredible! Lots of interesting background stories, and if you're (un?)lucky, you'll get the guy I did who made it sound like the fatal demise of the Concorde was a certainty, only a matter of time until something terrible happened. OK, no biggie, except when you're standing 10 feet away from it, and it's as real as any other plane you've ever traveled in.

AAD ON

At this museum, make sure you wait for a guided tour. It was fascinating to hear about fueling the SR 71 Spy plane.

Take all the pics you want.

An unconventional choice but if you want to unwind there is a Asian-style spa / bathhouse 20mins away in Centreville with pools, hottubs, sauna, fitness center etc, $35 admission for the day.

Spa World

It's in a mini-mall together with Korean restaurants (BBQ, chicken, Korean-Chinese) plus a huge supermarket and an IHOP. You would need a car (or cab ride) to get there from Dulles.

http://g.co/maps/ykyz9

How about land at 1120am and departure on a Sunday at 511pm? Really would love to see the blackbird and shuttle... Hour there, Hour back and an hour to see the highlights?

You should be able to do it - although you might have to take a taxi in one direction or the other. On weekends, the 50 cent shuttle leaves the airport 10 minutes past each hour starting at 11:10am - and leaves Udvar-Hazy at 30 minutes past each hour. Taxi fare should be around $13-$14. No problem getting a taxi from the airport to the museum. But you might have to wait for a taxi to be called from the museum for the return trip - check with the information desk inside the museum.

Note that the "real" shuttle will be arriving at Udvar-Hazy next week. A big series of celebrations is planned.

Here's a link to the 50 cent shuttle schedule: http://www.vatransit.org/route%20maps/Dulles2Dulles.pdf

You already know it won't be 10 hours-- maybe6-7-- given the time to get through Immigration and Customs and then come back for your onward, domestic flight. Under that if you need to allow time to rent a car and return it. The amount of time you'd actually have in DC, after finding parking, could end up being fairly limited. If it's a weekend, traffic will be less than on a weekday, obviously, but I still think it would be a bit of a rush. If it's your only chance to see DC at all, even a quick drive-by (so to speak) might be worth it.

How early you can check your bags for your onward flight (i.e., whether you can just hand over your checked bags at the transit desk outside Customs) can sometimes vary by airline, so first thing is to call them first. We're assuming you're on one through ticket, and that the two airlines have an interline agreement for the transfer of bags (e.g., not transferring to Southwest). I haven't seen the Air & Space annex near Dulles but would like to. I'd probably shoot for that in your situation. But it's your trip.

I have a 7 hour layover at IAD prior to an international departure. Arrival time is 3pm on a Friday. The Udvar-Hazy Center is only open till 5:30. If our flight arrives on time perhaps that's a way to kill a couple of hours. However, having never been to DC I wonder if it's feasible to see any of it. Hire a car/driver for 5 hours (expensive I know but maybe worth it for the efficiency of travel) and take in some of the attractions. However mid-winter at this time of day will be pretty dark. Are we really going to get to see much? The mall at night? The capitol I assume is closed. Any ideas on what to see? I assume if we leave IAD around 3:30, we are in DC by 4:30 (or is Friday traffic worse?), then leave DC by 7:30 and back to the airport by 8:30?

This is not sounding like a great idea.....but with a car and driver we could at least potentially see a bit of DC pretty quick.

A good thing about hiring a car is that it give a place to stash your carry-ons. You could get downtown by 4:30 or 5. The museums close at 5:30, so they're pretty much out, but you could stroll the Mall and get dinner.

A possible better plan is to see if the IAD-Udvar Hazy shuttle could get you there and back and then grab a cab to Reston Town Center where you could stroll around and get dinner in a more leisurely manner.

If you can get into the space center before close they may stop entry at 5:30 they MAY still allow people inside to finish their tour and maybe actually close the doors at 7.....something to look into.

I agree with Eric...Reston town center is more manageable and there are a bunch of restaurants.

To get to DC and come back can be a bear. At night the monuments of the white house Washington monument and Capitol are lit up so you can do a driving tour. It's a half hr drive with no traffic.

Another option is Tyson's corner where there are two separate malls with restaurants. Off mall property there are a bunch of restaurants as well. It's about 15-20 min from the airport

That's not going to happen. They start making "countdown to closing" announcements at 5:15pm or so. And then security "sweeps" everyone out of the museum by 5:30pm. You might get a few extra minutes past 5:30pm, but not much.

I wouldn't waste my time with Reston Town Center unless I had some specific shopping needs. It's almost all chain shops and restaurants. Much better to do some advance research and find a good ethnic restaurant not too far away.

Agreed. I like Thai Basil, which is on a shopping center on Route 50, a block or so west of 28.

herndon has a good collection of india indian restaurants. standard indian, but well prepared.