The prime minister made a speech at EasyJet in Luton on Tuesday.
David Cameron has warned that leaving the EU could push up prices of family holidays to Europe.
The prime minister said that Brexit would mean the value of the pound would fall, which would then put up the cost of going abroad.
He said based on Treasury calculations a family of four going to a European Union destination would see the cost of the holiday rising by an average of £230.
He added that it could also increase the price of air travel and roaming charges.
A full ban on mobile phone roaming charges in the EU will come into force in 2017.