(dissenting).
That the intervenors, non-certificated air carriers, cannot participate in certain air carriage unless the Board exempts them from the requirement of a certificate, is a normal feature of the system Congress created. In my opinion it does not authorize the Board to deviate from the system. Congress might, of course, have given the Board unlimited discretion to grant exemptions, but Congress has not done so. Section 416 (b) (1) authorizes the Board to exempt a carrier or class of carriers from a requirement of the Act when the Board finds that enforcement “would be an undue burden on such air carrier or class of air carriers by reason of the limited extent of, or unusual circumstances affecting, the operations of such air carrier or class of air carriers and is not in the public interest.” 52 Stat. 1005, 49 U.S.C.A. § 496(b) (1).
The Board’s exemption of the intervenors cannot be sustained on the theory of “an undue burden * * * by reason of the limited extent of * * * the operations * * *", because the Board made no such finding. It found that enforcement “would be an undue burden upon the applicants by reason of the unusual circumstances affecting their operations and is not in the public interest.” That certification takes time, and that surface-mail experiments may be brief, are circumstances affecting all *489uncertificated air carriers. It seems to me to follow that these are not “unusual circumstances affecting” the carriers the Board has exempted. Moreover, these are not circumstances affecting the “operations” of the carriers. For these and other reasons I think the Board exceeded its authority in granting the exemptions.