Passengers pass a sign that reads "Welcome to Schengen!" at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers arriving at the Henri Coanda International Airport pass under a Schengen Information sign, in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers make a selfie as they at Sofia airport, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. (AP Photo/Valentina Petrova)
Ebasa, a border police service dog, climbs on her handler during a media tour at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
A journalist passes Non-Schengen automatic border control gates during a media tour at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers ride an escalator at Sofia airport, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. (AP Photo/Valentina Petrova)
A passenger that arrived with a flight from Vienna talks to media members after being one of the first people to take advantage of Romania's entry in the Schengen Area without border checks by air and sea at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passenger passes posters announcing Bulgarias' accession in Schengen by air and water, at Sofia airpot, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. (AP Photo/Valentina Petrova)
From left: Yordanka Chobanova, the head of the Representation of the European Commission in Bulgaria, Maria Gabriel, deputy Prime Minister, Nikolay Denkov, Prime Minister, Jesus Caballero, Sofia Airport's CEO, press the red button during an official opening of Schengen borders by air, at Sofia airport, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. (AP Photo/Valentina Petrova)
Flight attendants arriving at the Henri Coanda International Airport pass under a Schengen Information sign, in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers arriving at the Henri Coanda International Airport pass under a Schengen Information sign, in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
A passenger that arrived with a flight from Vienna shows his passport after being one of the first people to take advantage of Romania's entry in the Schengen Area without border checks by air and sea at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
A woman passes a sign that reads "Welcome to Schengen!" as she arrives at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers pass posters announcing Bulgarias' accession in Schengen by air and water, at Sofia airport, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. AP Photo/Valentina Petrova)
A man touches a sign that reads "Welcome to Schengen!" as he arrives at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
A flight attendant passes a sign that reads "Welcome to Schengen!" as she arrives at the Henri Coanda International Airport in Otopeni, near Bucharest, Romania, Sunday, March 31, 2024. Romania and Bulgaria joined Europe's passport- and visa-free Schengen Area, applying only to travelers arriving by air and sea. (AP Photo/Andreea Alexandru)
Passengers coloured by green light attend a welcoming ceremony announcing Bulgarias' accession in Schengen by air and water, at Sofia airport, Bulgaria, Sunday, March 31, 2024. Romania and Bulgaria partially joined Europe's ID-check-free travel zone on Sunday, marking a new step in the two countries' integration with the European Union. (AP Photo/Valentina Petrova)