A couple of thoughts:
For starters they shouldn't be letting those little girls play with the bear in the airport. He is in a delicate state.
His fur looks pristine.
This has already been asked but I haven't seen an answer: What else was in the bag with the bear and the photo?
Person who lost the bear may have been a visitor to the airport rather than a traveller.
Person may have dumped the bear and photo and not want to be reunited with them - (perhaps it was given to a youngster by an elderly relative as a keepsake/parting gift, child thought 'yuk', 'I don't want this junk' and binned it)
Agree with Jane - I have no idea why airport staff would be looking for two passengers who travelled that day. And what names would you search for? Sadly, both children are likely to be dead by now. Bear and photo could have gone to anyone, or been sold in a house clearance decades ago ... there are numerous possibilities.
It probably doesn't matter if it is the same bear as in the photo or not - it belongs (or belonged) to someone, as did the photo.
Unfortuantely I think the only way the owner will be found is if they come forward to claim them.