In the U.S. the FCC issues a Restricted Radiotelephone Operators Permit for US pilots, but only for international use – it is not required while flying in the United States.

Most airlines require that applicants possess the Restricted Radiotelephone Operators Permit. The license is a one-time acquisition with no expiration.

To obtain your Restricted Radiotelephone Operators Permit:

1) complete and submit (per instructions), FCC Form 605 (Main Form 605)
2) complete and submit (per instructions) FCC Form 159 (fee processing form)

Per 2018 fee schedule, the fee amount is $70 with a payment type code of PARR

Electronic filing is also available at https://www.fcc.gov/licensing-databases/forms#159orig.