Fly through Frankfurt or Brussels?

I would be going Austrian Airlines to Vienna and a short hop into Prague.

Another option would be Air Canada into Toronto and transfer to a non-stop to Prague.

David, I am flying out of Prague to Chicago. Thanks!

I recommend you pick whatever flight gets you there with the least amount of connections and that has the lowest prices.

I might ask if you are doing a one-way, and if so, how did you get there to begin with? Shouldn't this be part of a multicity journey beginning in Chicago?

There are 4 flights a day from Frankfurt to Chicago on United/Lufthansa, there is only 1 a day from Brussels. If you fly through Frankfurt, you have back-ups in case of a hiccup, no such options from Brussels.

Sam - Thank-you! Yes it is part of multi-city, but as Chicago to Frankfurt is nonstop I didn't need advice on that leg. Frankfurt it is with being larger and having more options.

I see you are from Green Bay, I grew up there. Go Pack Go!!

I've never used BRU either.
I wouldn't miss the opportunity to visit a new airport and its sights.
It will be an opportunity to savor the local airport's fast food restaurants and duty free shop, the peculiar new seating arrangements in the gate areas, the gates themselves.
But above all else, I would also not miss the chance to experience sitting on the toilet of a new airport. Every airport offers its unique toilet experience that one cannot pass up. The different seats, the flushing system, the peculiar smells.
Definitely try a new airport.

Some people claim that Frankfurt is subject to nearby military airport airspace delays. But I think that may be an obsolete, cold-war era shibboleth. Frankfurt is so much larger than Brussels that you are better off there if there are any delays, volcano eruptions, or strikes. (Except in Frankfurt, of course!) Some people hate the long walks that can exist in Frankfurt. But I'm saying that size is a plus, in this case.

I understand that you are starting in Chicago, but Berlin is also quite an air hub, and nice place for a few days visit. Don't forget to explore code-shares that may not appear on your first searches. I fly United, but Lufthansa has many United code-shares, for example. (I start in Newark, not Chicago.)

Instead of trying to piece together the itinerary yourself, use a multi-city search function and then see the alternatives. Fullest possibilities come from the matrix at Itasoftware.com. It shows, for instance, only one non-stop flight from Chicago to Berlin, on Air Berlin, and not cheap compared to competing one-stops. (Never mind that Air Berlin is facing bankruptcy procedures; it is still flying.)
Using the matrix is an efficient way of finding a route that minimizes stops and costs. Let it do the work of building the itinerary, cheaper and faster than a freelancer. You can judge and compare the times of stopovers, etc.
Airports are not individual tourist destinations in my estimation; getting through them quickly matters more to me.
If you want to go to Berlin, however, it's a fine visit. The main airport is old, small, and seriously overloaded since the government capitol was moved back there. It accommodates relatively few transcontinental flights despite the city's importance. The new airport is so many years behind schedule that it upsets major stereotypes about German efficiency. Onwards in Europe from Berlin, after a stay, might be better handled with a no-frills European airline one-way, as seen at www.skyscanner. com

I do use a multi-city matrix and we do not have time for a stop in Berlin, but thank-you!

I hereby rule that when Roberto da Firenze posts humor, it must be accompanied by annoying emoji's 😉😋 to indicate such. Otherwise, I will be forced to send him a bill for cleaning the coffee out of my keyboard.

Rhine Main Air Base closed in 2005, so there hasn't been any disturbance from military flights in Frankfurt for the last 12 years.

I have flown through both Brussels and Frankfurt. On the way back, I would choose Brussels. It is dmall so less annoying after a good vacation. Disclaimer: I suffer from Returner's Remorse, so I need a peaceful exit. And to stock up on Neuhaus chocolate.