Gibraltar was doing just nicely until a group of 18 million people decided that Britain's future should be outside the European Union. All of a sudden a large black cloud hung over "the Rock" and to some extent it is still hanging there today. Brexit is the chief concern of the 30,000 Gibraltarians; they fear that Spain may introduce a "hard border" which would severely hamper cross border trade and tourism. Many have horrible memories of when Spain closed the border, effectively isolating Gibraltar. And that is what some fear at the moment.
Gibraltar relies heavily on tourism and there was a hope that the new Gibraltar air terminal could be used by tourists going to both sides of the border. This has never happened because Spain doesn't want to get involved. There is a school of thought, not shared by many sceptical Gibraltarians, that Brexit offers an opportunity for Britain and Spain to sign an agreement which would allow Gibraltar to flourish. Perhaps the new terminal could be used to open up the far south of Spain to tourists.
The Gibraltarians want to work with Spain but it is all one-way traffic at the moment. There is a big difference between Gibraltar and the area around the border on the Spanish side - money and income. Gibraltar is affluent with its new buildings and developments but the Spanish side struggles economically. I do not doubt that the Gibraltarians will find a way forward but their life just got more difficult again.