Air Service Improvement Act

Air Service Improvement Act - Amends the Federal Aviation Act of 1958 to direct the Civil Aeronautics Board to consider maximum reliance or competitive market forces in the airline industry as being in the public interest.

Limits the Board's present authority to include limitations in certificates to engage in supplemental air transportation.

Exempts air carriers which engage in interstate air transportation solely with aircraft below a specified passenger or cargo limit from being required to obtain a certificate of public convenience and necessity if the carrier conforms to such financial responsibility requirements as the Board may impose.

Directs the Board, in the event an air carrier holding nonstop authority to engage in scheduled air transportation between any two points does not exercise such authority for at least 180 days during the preceding 12 months, to issue a certificate to an applicant to engage in nonstop air transportation between such points. Directs the Board, following the issuance of such a certificate, to institute a proceeding to determine whether the usused nonstop authority should be revoked.

Authorizes specified types of air carriers to apply for certificates to engage in nonstop service between three additional pairs of points. Requires the Board to issue such certificate within 30 days unless the applicant is not fit, willing, or able to provide such service.

Restricts the Board's authority to find that any proposed rate, fare, or charge is unjust or unreasonable on the basis it is too low or high.

Sets forth time limitations for the determination of route applications by the Board.