14 CFR §21.213

1. (a)A manufacturer who is a United States citizen may apply for a Class I or Class II provisional airworthiness certificate for aircraft manufactured by him within the U.S.
2. (b)Any holder of an air carrier operating certificate under Part 121 of this chapter who is a United States citizen may apply for a Class II provisional airworthiness certificate for transport category aircraft that meet either of the following:
   1. (1)The aircraft has a current Class II provisional type certificate or an amendment thereto.
   2. (2)The aircraft has a current provisional amendment to a type certificate that was preceded by a corresponding Class II provisional type certificate.
3. (c)An aircraft engine manufacturer who is a United States citizen and who has altered a type certificated aircraft by installing different type certificated engines, manufactured by him within the United States, may apply for a Class I provisional airworthiness certificate for that aircraft, if the basic aircraft, before alteration, was type certificated in the normal, utility, acrobatic, commuter, or transport category.