US President Donald Trump’s highly-controversial travel ban has caused a 6.5 per cent drop globally in flight bookings to the US, a move which could cost the country billions in lost spending on tourism.

According to the the National Travel and Tourism Office, in 2016 visitors coming into the US spent US$247bn (€233bn, £199bn). If those numbers declined over the year at the same rate as the drop in bookings, that would amount to a loss of roughly US$16bn (€15bn, £13bn).

Forward Keys, a travel statistician firm, said that searches and booking for trips to the US had declined by 17 per cent since the President’s election. Additionally, those that were looking at US trips had insead changed course, with Russia and Canada top of the hot spots, along with The Caribbean, Mexico and Thailand.

Now dubbed the “Trump Slump”, Euromonitor first predicted the effect at the World Travel Market in November, saying that over the next five years, the US economy would reduce by just under 5 per cent, meaning that instead of a predicted growth of 1.5 to 2 per cent for 2017, the US economy would have marginal growth - around about 0.3 per cent this year.

In addition to affecting the US and its overseas travel markets in terms of visitor numbers, Euromonitor also predicted a weakened dollar, which has actually largely remained stable since Trump’s win, slightly rising from 99.13 to 100.91 on the on the US Dollar Index – a measure of the value of the dollar relative to a basket of six major foreign currencies.

Signed on 27 January, Trump's executive order attempted to block people from seven Muslim-majority nations from entering the US for 90 days. The order was later declared unlawful by a US court, though the President is still trying to push it through in a new format.