We're currently booked with infant twins in 64A and 64B-- are two lap children allowed in one row?

We've been kicked out of our single-row seats right before boarding on other carriers because of the lack of air masks. Apparently, there is only one additional air mask per row. I want to make sure we are able to pick our seats if we need to be separated by an aisle.

Oh, and before we derail the conversation, they are super well-behaved. Never cry. So, we're comfortable bringing them in First and the upper-deck....