随时随地订机票、无陪购票、添加儿童婴儿

What's the difference between business class and first class? Why are they often lumped together when booking tickets?

Can I transfer my plane ticket to my husband so that he can take my 7-year-old child on the plane?

Can I still add a child ticket 7 days after buying an adult ticket?

Stopover and transit, sound similar, but are they actually the same thing? Which is more cumbersome?