The long-running dispute over Gibraltar is again pitting Spain against Britain as Brexit negotiations advance with the European Union. Spain wants joint management of the tiny airport in Gibraltar - but the UK sees things differently. Al Goodman reports from the southern tip of Spain.

It's not one of Europe's busiest runways. But the airport in Gibraltar may be the most contentious on the entire Continent. Especially now, with Britain negotiating its exit from the European Union. Because Spain, which ceded Gibraltar to Britain 300 years ago but still claims the Rock, wants joint control of the airport, as part of a Brexit deal. But Gibraltar's government flatly rejects shared management of the airport.

JOSEPH GARCIA GIBRALTAR DEPUTY CHIEF MINISTER "What we are saying in Gibraltar is that we should be part of the new UK-EU aviation agreement that has to be signed up to, once the UK is outside the European Union."

Yet Spanish Foreign Minister Alfonso Dastis warns Gibraltar's airport could be left out of Britain's air access to Europe's skies-- after Brexit-- if there's not joint Spanish control of the airport.

AL GOODMAN GIBRALTAR "Many people in Gibraltar hope the airport will not disrupt the negotiations over Brexit. But every time a plane lands or takes off, there's a different kind of disruption right here."

The road - connecting Spain to Gibraltar - is blocked, because it's part of the runway. Waiting is normal here. Slowing down thousands of Spaniards who cross the border to work in Gibraltar. And tourists coming to see the Rock, and the airport, still contested by Spain and Britain.

FRANCIS KEEPFER TRAINEE SOLICITOR "If Gibraltar is going to stay in Britain's control, then I suppose it's still British territory and I'm afraid Brexit doesn't really make a difference."

But this Spaniard says Spain should have shared airport control.

JESSICA LOPEZ CASINO WORKER "I agree. I used to live in London for six years and I'm looking for a job in Gibraltar, after all. So for me, could be better."

The airport and Spain's visiting workforce for construction and services are vital for Gibraltar's economy. Hundreds of small businesses here worry about Brexit, And their federation leader says they're making contingency plans.

JULIAN BYRNE GIBRALTAR FEDERATION OF SMALL BUSINESSES "Gibraltar is not a place where we sit down and wait what's gonna happen. You know, we've always had to fight for our future, that's what we'll do again and what we're doing now."

Gibraltar's 32,000 people have voted repeatedly to remain British. But with so many Brexit issues for Britain to handle, including Spain's demand, some here wonder if darker skies might be coming for the Rock. Al Goodman, CGTN, Gibraltar.