The United Nations Children's Fund, UNICEF, has joined forces with travel tech company Amadeus so that each time you book a flight, you're also making a small donation.

The two entities recently signed an agreement that lets travel providers raise funds for UNICEF by giving buyers a choice to donate a few bucks in addition to whatever they're paying for the trip.

This is the modern version of rounding up your total at the grocery store for charity; it is also being described as today's "Change for Good," program, which allowed passengers to donate spare change after their trip abroad, and raised $150 million since 1987.

The concept behind this move is to give back to the communities in the places where people visit.

"Opportunities like this are ways where people can share some...wealth while they're enriching themselves as well," UNICEF International Fundraising Director Tim Hunter told Mashable. "Maybe there's a dynamic in there where you're targeting the right kind of people and at the same time people are maybe thinking, 'oh, I'm going to be enjoying myself and having a good time, I'm also going to try and improve the lives of children and families in other parts of the world who are not quite as lucky as me."

The search engine Amadeus provides bookings for 110 airlines worldwide, and processed 50 million bookings in 2012. Take that number, figure between 5-10 percent of folks booking their travels might donate a dollar, and there's $2.5 million plus being given to a worthy cause.

"In terms of the capacity, the number of bookings that Amadeus partners through its various partner airlines runs into the millions, and therefore we believe this has the opportunity to raise over the next few years millions and millions of dollars," Hunter said.

Amadeus is currently talking to a few airlines in hopes of bringing them in, such as Iberia, Quantas and Finair.

Each airline can specially customize their participation, so that, say, an airline serving Argentina can donate their share to hungry families in Buenos Aires.