For all the travelers with a one way flight ticket who are uncertain about entry into a Schengen Area country.
My mom had this issue flying from Chicago to Prague with a transfer at London Heathrow. Virgin Atlantic was set on not letting her fly to London because of this “rule.” After talking with the airlines/ debating about the regulation/ skyping with me, my mom was lucky that a Polish baggage man spoke up and told the present manager that you do not need a return flight ticket to enter the Schengen Area.
The Czech Republic is part of the Schengen Area which is a group of countries with open borders between them. This area includes 25 European Union countries with the exception of the United Kingdom and addition of Iceland and Norway. If you read through entry and exit requirements for the Schengen Area, you will not find a requirement stating that a return ticket is needed for tourists. To be certain of this, I confirmed this with two representatives from the US Embassy in Prague. There is no special rule requiring travelers to have a return ticket when they enter the Czech Republic.
It is unusual to fly to Europe from the US on a one way ticket without a visa. This may raise questions at customs. From my understanding and from no official source, customs officials can deny you entry into the country if they believe you are trying to illegally immigrate. This does not seem to be a problem for Americans traveling to the Czech Republic, especially with the lax customs officers at Vaclav Havel Prague Airport.
Airlines have two reasons why they will misinform you and not allow you to board the plane without a return ticket:
1) An airlines is responsible for you if the country to which you are traveling denies you entry. One online discussion board on the topic mentions a situation when an airlines had to pay for food vouchers and an airport hotel room when a traveler was denied entry into the country. Other discussion boards claim that an airline is responsible for sending you back to your original departure country if you are denied entry.
2) Airline companies are in the business of selling tickets. So, if you find out last minute that you cannot get on your flight, let alone through security, you are likely to buy an expensive one way ticket from their company.
Other countries outside of the Schengen region will probably have different rules and regulations. If you are unsure about entry requirements to a country you are traveling after reading the websites of the Department of State, the American Embassy in Country XYZ, and the XYZ Consulate in your country, make a phone call or write an email to the consulate and/or embassy.
To avoid this situation, buy a round trip ticket if you can. Round trip tickets are cheaper and more convenient. If you really want to be indecisive or carefree with your travel plans, just be able to stand your ground at the airport in the US. Ask for a manager, ask for proof, and be confident in your ability to fly into the Schengen Area without a roundtrip ticket. At this point, you probably know more about the topic than they do, so do not be timid.
I do not accept any liability for botched travel plans. This is just my experience and understanding.
Fill a large bowl with water and remember this
If she floats on her side eat her with pride
If she stands on one end in to the baking pan
A floater is a stinker and out the door you must fling her