So my local FB group, always lights up, whenever people talk about checking car seats (to do or not to do) on planes. Of course, it leads to people arguing over why there should not be lap infants because it not safe... yeah, I think you do what you have to do (no judgement here)...

So I know Car seat experts (CPST) say the best way to travel with car seats is to check it in the manufacturers' box.

I'm going to try to do this but in our case we have twins. We bought a seat for one twin and the other will be a lap infant. So I know I can bring one car seat directly on the plane. But the second car seat will be placed in the box and checked (gate checked or baggage check).

My question is what happens if I don't know whether or not I will get a free extra seat for the second twin. (Most likely will happen if the flight is not full. Won't happen for the flight before 4th of July, but return flight might be emptier.) Do I bring the second car seat (in the box) to the gate and take it out if I can get a extra seat? If I do get the extra seat, do I just send an empty box to be gate checked? Seems a bit weird. Do I bring tape so I can seal up the box?

Has anyone done this?

Yes, this is the recommended way to travel with a car seat per car seats experts. If things get difficult, I may just bring both car seats without the box or just bring one in the box.

Yeah, these are all things I should do.

Oh, I will be traveling with cheaper convertible car seats (Cosco Scenera worth $40-$50). A few months ago, I would have taken my Diono car seats but my sister recently went to PR and her car seat was lost! She never got it back. Yeah, I'm not sending a $200 car seat to be possibly damaged and/or lost.