This lady in on a power trip.
Speaker of the House is a very big post and she does have some perks coming to her. But, a jumbo jet bigger than that of her predecessor is just a power trip. She wants to be seen as powerful and that that power commands big perks and one of those perks should be a plane as big or close to that of the president of the U.S. Next, she's going to be insisting that the plane also be equipped with gear such as Air Force One which allows the president to virtually run an airborne White House.
It takes a big plane to get throught that marble ceiling.