多谢各位,现在明白了,查了united的政策,果然是这样的。顺便问问其他航空公司也
是这样的吗?
Ticketing
Infants under the age of two traveling without a seat within the United
States, Puerto Rico and U.S. Virgin Islands do not require a ticket. All
infants traveling internationally, including infants traveling to Canada and
Mexico, must have a ticket, even if no seat is purchased and they are
traveling as a lap child.
Infants traveling between the U.S. and Canada, or from Mexico to the U.S. or
Canada, only pay taxes on the ticket. Infants traveling without a seat to
other international destinations are charged 10% of the adult fare at the
time of infant ticketing (it is usually less expensive to purchase the
infant ticket in advance). Infants traveling on an adult's lap on front
cabin awards or upgrades must pay 10% of the front cabin fare in applicable
markets.