When is a charter a “public charter” as opposed to a “private charter”? According to 49 CFR 1540.5, “Private charter means any aircraft operator flight (1) For which the charterer engages the total passenger capacity of the aircraft for the carriage of passengers; the passengers are invited by the charterer; the cost of the flight is borne entirely by the charterer and not directly or indirectly by any individual passenger; and the flight is not advertised to the public, in any way, to solicit passengers or (2) For which the total passenger capacity of the aircraft is used for the purpose of civilian or military air movement conducted under contract with the Government of the United States or the government of a foreign country.” Public charter, on the other hand, “means any charter flight that is not a private charter.”
Why does this matter? Well, one of the biggest reasons is the difference between the security procedures that are involved/required for a public charter versus a private charter. Depending upon the size of the aircraft, and if applicable, the security requirements for a public charter are more strict and, as a result, more expensive. Thus, the classification of a charter operation as public will significantly increase the overall cost of the charter to the charterer and its passengers. A charterer will need to make sure all of the criteria are met for private charter in order to avoid the default classification as a public charter.
