Which car seat to bring on plane?

Hi everyone,

My husband and I will be travelling with our 2 under 2 while both kids are 2 months and 17 months. We plan to buy three seats and use the Cosco Scenera Next car seat on the plane with us, while we gate check our EvenFlo Pivot Module infant bucket seat, base and stroller frame.

We were thinking that the Scenera shoulder straps could be adjusted depending on which kid wants to sit in it. But since the EvenFlo bucket seat costs more (is more valuable than the Scenera?), should we use this on the plane instead? Our toddler is just under the max height and weight of the bucket seat, but normally uses a Graco car seat in our minivan.

Any help is appreciated.