KUSA - Every year, more than 50-million passengers make their way through Denver International Airport; about three million of those are going abroad on direct flights. It is a number that will climb next year.

"The demand is continuing to grow," said Laura Jackson, vice president of air service development at DIA.

Airport and Volaris airline officials welcomed the first flight between Monterrey, Mexico and DIA on Thursday. The daily flight will operate year round, with seasonal adjustments. It is one of 20 international direct routes from Denver, with others coming next year.

"So, next year, Southwest will inaugurate service to Belize,” Jackson said. “It's a brand new international market for us as well, so that service is starting in March."

On top of that, Denver's Frontier Airlines began its service to Cuba on Thursday morning. Though not direct yet from Denver, passengers heading there from DIA say having commercial service to new places makes travel easier.

"In the past, it's been on charter airlines,” said said Jack Lopez, who lives in Golden and was heading on Frontier to Cuba for the first time ever, to meet his father’s family. “To go on an American airline, especially Frontier out of Denver, to Miami and then onto Havana, I think it's fantastic, it's exciting."

Beyond that, current airlines will also be expanding their international routes from Denver this summer.

"We also have 15-percent more capacity to Europe coming next summer,” Jackson said. “So, Lufthansa will increase the frequency to Munich going to daily service and Iceland Air is going to be offering nine flights per week in the summertime, so on Tuesdays and Fridays, they'll have two flights to Reykjavik."

However, they said there is also room for expansion beyond Europe.

"We definitely would like to see more non-stop service to Central America and South America – we see that as a region that's growing,” Jackson said. “In addition, China is a market that we're continuing to look at and focus on and try to build demand to that region."

DIA currently serves eight different countries with direct international flights. They say the country with the most flights from Denver is Mexico.