NEW YORK (TheStreet) -- Britain-based airline carriers Easy Jet and IAG, as well as some others, are taking a hit after the U.K. voted to exit the European Union on Friday, CNBC's Sara Eisen reported on "Squawk on the Street" Monday. 

The British pound hit a 31-year low against the dollar on Monday, which will make trips to Europe from Britain more expensive.

The U.K. could potentially be locked out of Europe's open sky agreement, which allows any European or U.S. airline to fly freely between countries. This has been very beneficial for airlines based in Britain but could make it harder to launch new routes in Europe, harder to set prices, could add various new regulations and potentially even tariffs, Eisen said.

Additionally, large U.K. pharmaceutical companies such as Glaxo and AstraZeneca have only held up because they benefit from the weaker pound as they do most of their business overseas.

The biggest EU agency located in the U.K. is the EU's FDA in London. There are already demands to have the agency moved to another European city. This creates uncertainty as to what it could mean for British drug approvals, pricing, funding research and more, Eisen added.

Property stocks are also taking a hit in the wake of Brexit. Commercial real estate is expected to become less demanding in London and the U.K. because companies, especially banks, will not have the EU passport or access to open market in those locations.