I'm seriously considering taking the chance and booking the short connection. I know I can book my seats after I book my flights. The question I have is. can I see the seat availability before I purchase my ticket?

I do have a fear of flying and I would like to sit next to my husband if possible. If it looks like it's limited seats left I might not booked it. Is there a website I can go to to see this or does anybody else have any suggestions how to see this?

Are seat selections only available 24 hotel before check in or can I pay extra to reserve ahead of time