Except as provided in subsection (b), if a dependent accompanying a member of the uniformed services who is stationed outside the United States or in Alaska or Hawaii and who is on active duty for a period of more than 30 days requires medical attention which is not available in the locality, transportation of the dependents at the expense of the United States is authorized to the nearest appropriate medical facility in which adequate medical care is available. On his recovery or when it is administratively determined that the patient should be removed from the medical facility involved, the dependent may be transported at the expense of the United States to the duty station of the member or to such other place determined to be appropriate under the circumstances. If a dependent is unable to travel unattended, travel and transportation allowances may be furnished to necessary attendants. The dependents and any attendants shall be furnished such travel and transportation allowances as specified in regulations prescribed under
section 464 of title 37. Travel expenses authorized by this section may include reimbursement for necessary local travel in the vicinity of the medical facility involved. The transportation and travel expenses authorized by this section may be paid in advance.