As family of four have a weekend in Washington at the end of February (with baggage). Our flight back to the UK is at 10pm and we are thinking that we would visit the Smithsonian National Air and Space Museum's Udvar-Hazy Center on our last afternoon.

Our current thinking is that we'd get the silver line out to IAD and then a bus/taxi to the museum (and back) and so are seeking advice on what we can we do with our baggage as it clearly doesn't make sense to leave at the hotel (in central DC).

Obviously this is a specific trip but I'd hope that advice about baggage is fairly general - eg if there was a company in DC that collects in the morning for the flight later in the day (which we have in London).