cat;
1st class is a nice option, however, most 1st class flights have only two seats per row. Chances of an open seat to situate your little one and reset your lap will be slim.

In the past (when our daugther flew gratis), we requested an aisle and window seat at check in, while kindly informing the ticket agent that we hoped the center seat remained unoccupied. To our pleasure we were able to secure the center seat on
all our trips aside from one return trip.

Alas, now with two children, both above the age of two, we are subject to the airline airfare and seating arangements.

Ralph