Trying to find cheapest flight to Washington DC from any city in Europe

No idea if this would work, and it would still involve some city by city checks but... if you go to Google Flights explore and input from Washington DC to Europe, plus your dates, lots cities pop up. You could pick a few showing the lowest prices then see what the opposite direction flights would cost.

Look at Fly Play, a low cost airline from Iceland that flies from BWI and has round trips to Paris for under $600 July 3-Aug 21 as an example.

Late July to late September could be even less.

kid is planning to spend a few months in Europe this summer.

You are aware of Schengen limits?

One way fares to/from Europe are usually pricey and is much better to book a r/t or multi-city ( aka open jaw) journey

Also be aware when your son arrives in a European airport, immigration wants to see return ticket to US or proof they do intend to return to US.

Out of Dulles Airport, I just see the big legacy airlines flying to Europe.

Baltimore has Play and Icelandair that may have some budget trips connecting through Iceland.

The bargain trips are out of the NYC area and an hour north of NYC. Boston often has great airfares to Europe too.

Both PLAY and Icelandair also fly out of Dulles so no need to go to BWI unless it is closer to you.

If you are looking for a one-way ticket, I would also check Aer Lingus out of Dublin, TAP out of Lisbon, and Turkish Airlines out of Istanbul.

Copenhagen (CPH) to Dulles (IAD) on July 29th is $401 one-way on PLAY. 1 hour connection in KEF.

Bag fees etc would be extra.

That’s the best deal I’ve found so far.

Thanks for the input! After a painful amount of clicking it's looking like Play from Copenhagen is the best bet. Really wish there was an easier way to find flights like this. I tried several of the AI tools but none could handle this sort of request. Maybe I need to make an app myself!
So some of the comments/questions:
- The reverse flights of cheapest explore option flights are where we started. In the end it just takes a million searches. Complicated by the fact we have multiple airports in the DC area we can use.
- Saw some reasonable flights through Paris but avoiding that during Olympics. Expect that is going to be massive crowds and security issues.
- Aware of the 90/180 rule. Kid already has seen 20 countries in the last few years but had not been to Europe in the last 6 months. Will be there less then 90 days including some outside of Schengen.
- In Maryland. Usually BWI or IAD are about the same but with the beltway construction near Tyson's BWI is a more reliable choice.

i still like google flights. They even have a search DC to EUROPE. Dig through the results till you find a few cheap destinations. Then search those destinations using the chart that show the cheapest dates to fly. Then go basic economy or what ever the cheap catagory is on the particular airline.

Really wish there was an easier way to find flights like this.

Take a look at Google Flights in the future. With a little input it will give you a lot of information. Remember always book with the airline, deals through third parties can create a lot of issues. If there is a problem the airline deals with it. If you book through a thid party site, they have to deal with it and the result may not good for the passenger.

Is the cost of the flight the only factor when determining "cheapest"? What about the cost of transportation getting to the departure city, the cost of lodging in the departure region, etc? It may be much cheaper to travel through Poland as opposed to Scandinavia - a flight costing $100 more out of Warsaw could be cheaper in the long run.

Also, won't a low fare from the States suggest a comparable low fare coming back?

Also, flights to JFK plus train fare could be cheaper than a flight to Dulles.

markcw makes really good points above. It's easy to get tunnel vision when obsessed with a single search criteria: you might save a few bucks on the flight, but don't ignore the many other opportunities for much greater cost savings elsewhere in the bigger picture.

And speaking of the bigger picture...it's not always only about finding a way to minimize costs, to the exclusion of every other consideration. I always end up shaking my head when I see folks who seem singularly obsessed with finding the absolute cheapest anything (including flights) while ignoring every other equal (or greater) consideration, eg where do you want to go and be? There are places I want to go and experience, and there are some places I would not waste my time in no matter how cheap the flight was. Everyone likes to save money, but generally saving money is not the reason most of us go places, so keeping things in perspective is always a good idea.

Sounds like this "kid" is pretty well-traveled. Maybe he/she would benefit from participating in figuring out flights and other travel costs. Teach a man how to fish, as they say...

Good luck.

Trust me there is a giant shared doc with flight costs, city pairs, lodging and food costs, etc. Mine has a pretty generous budget but they have a friend joining for part of the trip who is a grad student on a very tight budget. So they really have to maximize value and minimize risk.
- Google and SkyScanner are the main research tools but all flights are booked direct (that whole minimize risk thing). Trying to reverse city pairs kind of works but flights may vary by hundreds of dollars just a few days apart still takes a lot searches.
- Definitely looking at flights out of NY as well
- Looking at the whole picture on costs. Also has (a very long) list of places they still want to see or would like to spend more time in, and a list of been there done that cities they don't care to repeat. Also looking to avoid getting too close to the war zone in the Ukraine.
- "Kid" is very well traveled and does a lot of their own planning, but travel dates/budget just became clear and they are up against a big project deadline, so I'm helping out where I can.

If I read this right, the outbound is not the issue (nor should it be), since Google Flights
works great if you use the map and input the origination airport. Note that the initial
input goes by specific date or month, but if you pick a destination city, then "view
flights", and then click on the calendar date, a two month calendar window pops up
showing the cheapest fare on each day.

For the return, yes, it is not quite as simple as outbound, but, you can again use the
map function. Position the map over the eastern US, and then input the possible return
cities into the query box (leaving the destination blank). You'll then see the cheapest
flights in a month (e.g., August) for all the cities in the map space. As before, if you click on
a city, and then "view flights" and click on the date, the calendar window pops up.

Since the return trip appears to be open-ended, you might be happy to grab a cheap fare
on whatever day it happens to be available on.

Here's a URL (I hope this works) that shows what I mean:

Berlin to somewhere in the Eastern US in August