14 CFR Part 399: Statements of general policy, including unfair and deceptive practices
Part 399 holds the DOT’s policy statements, and among them the rules on how fares may be advertised. The best-known is the full-fare rule: the total price a customer will pay has to be the most prominent figure in an advertisement.
It is also the part under which the DOT articulates what it treats as an unfair or deceptive practice, which is the basis for a large share of its enforcement actions against airlines.
Why a passenger would open this part
This is the part behind the price you see, and behind most DOT fines. It was amended on 2 July 2026, making it the most recently changed part of the six.
This summary is ours. The regulation’s own words are quoted below and linked in full.
What 14 CFR 399.84 says
“charges included within the single total price listed (e.g., government taxes) may be stated separately or through links or "pop ups" on websites that display the total price”Read 14 CFR 399.84 in full
The sections that matter to you
Of the 4sections in this part, these are the ones that bear on what a passenger gets. Which sections belong on this list is our judgement, not the regulation’s.
- § 399.79Unfair and deceptive practices
- § 399.84Price advertising and opt-out provisions
- § 399.85Notice of baggage fees and carry-on restrictions
- § 399.87Prohibition on post-purchase price increases
Every time this part changed
- Apr. 25, 2011 76 FR 23166The full-fare advertising rule takes effect.
- Apr. 30, 2024 89 FR 34674
- Jul. 2, 2026 91 FR 40371The most recent change to any of the six parts.
Dates and citations are taken from the source note printed with the regulation. Entries with no description are ones the source note records without explaining, and we do not guess at what changed. All six parts side by side are on the rights timeline.
What we have not covered here
Part 399 is large and holds policy statements well beyond passenger rights. We cover only the sections that bear on fares, fees and deceptive practices.
What this means in practice
Row30 provides data journalism and education, not legal advice. We are not a law firm and do not represent passengers in legal proceedings. For advice about your own situation, consult an attorney.