premise: The airport was declared " closed " and we had to sit for 1.5 hours inside the plane . Apparently its related to trade union issues . Off we got , happy to arrive in the US of A and given we were the first plane to disembark rushed to passport control to avoid long lines of irritated passengers detained in other flights due to the storm . David joined the US citizen line and quickly went by , while Vero and Marcos slowly reached the customs officer in the " rest of states " line . Problem Number 1 : when we handed over our passport and customs slip to the officer he requested a green visa slip . Why did the officer request the visa slip ?
hypothesis: The trade union issues required visas to be displayed .