never traveled with my babies before. they will be 21 months at their time of travel. we have a side by side double stroller and it wont fit in our overhead, lol. BUT i need it until we get on the plane. how does it work? we will be flying jetblue and i am unsure as to how everything works. do they take it away when i enter the plane? where does it go? can i bring it with me up TO the plane, etc?