14 CFR 303.42 - Comments on application.
(a) Unless a different comment period is specified in the weekly list, or in a notice of filing published in the Federal Register, any person may file comments, responses to the application, and/or a request for a hearing within 21 days of the filing of an application.
(b) Comments supporting or opposing an application or proposing conditions and responses thereto shall state with particularity the factual basis on which the person commenting relies, and provide affidavits or other material in support of the factual basis, if appropriate.
(c) Requests for a formal oral evidentiary hearing must set out with specificity the material issues of fact in dispute that cannot be resolved without such a hearing. Vague, unsupported allegations will not suffice.