Hi everyone! Happy Holidays!
I am flying to Tenerife with my 1-year old baby and my husband. We are both on one ticket (booking).
A few weeks later I also bought my sister a ticket to join us, but we are on seperate bookings and unfortunatelly it is imposible to connect them, i alread asked.

What are my options to get the seats together? The plane seat map shows 3 seats sitting together.
I assume they would assign me and my "infant" to the window seat and my husband in the middle as we are on one ticket?! Is there any hack we could use to get my sister to join us on the isle eat in the same row?!

Booking seats in advance for each person could cost us hunders of euros, so this is the last option. During the check in time does it let you also select and pay for the seats or are all seats assigned automatically during check in?

Any thoughts?