Over the last several years I have travelled extensively around the US and back and forth between the US and Canada. I rarely encounter issues. Yes, I have had luggage delayed or flights cancelled/delayed and once United actually lost my booking not once but twice on the same day. And there was the time I got stuck in Florida for 3 days after a major storm ripped through Chicago, Washington, NYC, Boston, Philadelphia and the backlog took that long to clear. Oh, and who can forget the cat that got loose on my Air Canada flight.... But, those incidents have occurred over the course of 5 years and I'd consider that pretty good.

For anyone else that travels, I would never present cash at the rental car agency that used a credit card to secure the rental. Securing a rental puts a hold on your cc which doesn't get released for up to 15 days when you pay by cash. It's better to pay an advance on your cc instead of the rental agency.

As for scheduling special needs equipment, loudly insisting at the time usually gets you action, even better if you can get the infant crying at the same time. ;) And, the extra fee, well, if you book through the airline and had retained all documentation from the flights into the US showing the infant's boarding card, etc, that can help. If you booked through a charter service, that complicates matters since sometimes the operating airline doesn't get the info from the charter service and your only recourse is to pay and then get the refund from the charter service.

Hopefully, the fun that your son and his family had previous to the airport encounter more than makes up for the inconveniences.