A romantic gesture
It seems this guy had a big decision to make and had some time to think about it before his girlfriend returned from her trip. When he decided he was ready to fully commit to the relationship and take on the role of a father, he chose to let Anna know in the most romantic (and public) way possible.

The first thing Anna saw when she arrived home after her work trip was this heartwarming message. We might have mixed feelings about sharing such an intimate moment with other airport visitors, but hopefully, Anna appreciated this gesture for what it was.