British Airways has decided to ground its Washington flights for a second day. BBC News Online looks at what you can do and what rights you have if your journey has been disrupted.
If my flight is cancelled, how can I get my money back?
British Airways says it will offer customers who were booked on cancelled or suspended flights a refund of the original ticket price, the possibility of re-booking or an alternative route.
BA operates 33 flights to the US each day, and with American domestic airlines offering an extensive range of internal routes, getting to Washington should still be on the cards.
Any compensation over and above the ticket price will be decided upon on a case by case basis, BA says.
Passengers seeking information can ring BA on 0870 850 9850.
What if I've already booked accommodation in Washington?
People with accommodation bookings in Washington should contact their travel agent or hotel company to seek alternative travel dates or destinations, or to ask for a refund.
If this is unsuccessful, people who paid using a credit card have another potential route.
If you paid with a card, bought direct, and your ticket cost more than £100, you could lodge a claim with your credit card company.
This is because under Section 75 of the Consumer Credit Act, the credit card company is jointly liable.
This also extends to travel services.
Will my travel insurance pay if I am concerned about the security situation and, in general, don't want to visit Washington ?
Travel insurance will not cover "disinclination to travel" and many policies have exclusions for cancellations for this type of problem.
Check your policy to find out more.
If the Foreign Office, however, deems your destination unsafe, tour operators and airlines will normally step in and offer alternatives.
There is currently no warning from the Foreign Office against travelling to the US, but it has said that passengers should expect more delays at airports and tighter security.
Where can I find out whether it is safe to travel to a particular country - and keep up to date with the latest news?
The first port of call for up-to-date travel advice is the Foreign Office.
Advice can be obtained by calling 0870 6060290 or through the department's website.
BBC Ceefax page 470 and the government's UK Online portal also carry the latest warnings.
Where can I get more information about my rights?
The Air Transport Users Council (ATUC) can investigate queries from passengers on scheduled flights.
It can be contacted at: CAA House, 45-59 Kingsway, London WC2B 6TE. Telephone 020 7240 7071.