Many business people choose air transportation because it is

Many business people choose air transportation because it is fast ,offers convenience,and it is not very expensive.
it is fast ,offers convenience,and it is not very expensive.这三个是平行的,但是第一个和第三个都是 it is +adj.而 offers convenience 是 vi +n.这样就不平行了,可改为：
Many business people choose air transportation because it offers us convenience ,and it is fast and not very expensive.
Thank you~
不懂还可以问.