Cargo Aircraft Only label (CAO)
The package holds dangerous goods that the air rules allow on cargo (freighter) aircraft but not on passenger aircraft. It tells the airline and its ground staff to load the parcel on a cargo aircraft only.
Who puts it on the box
The shipper. Under 49 CFR 172.402(c) every person who offers or transports by aircraft a package of hazardous material that is authorised on cargo aircraft only must put this label on it. A common case is lithium ion batteries shipped on their own rather than packed with or inside equipment (UN 3480): an ICAO amendment to the 2015–2016 Technical Instructions changed them from passenger and cargo aircraft to cargo aircraft only.
How to read it
Look beside the hazard label or the battery mark: for lithium batteries the ICAO packing instruction wants the label on the same surface, near the lithium battery mark, when the package is big enough. The label is about aircraft only. On a van or truck it changes nothing — an ICAO panel report notes that manufacturers leave it off because it “would not be required for the road segment of transit”.
If the parcel is in your hands
If the parcel was delivered to you, the label is a loading instruction for airlines, not a warning about opening the box. If you send the contents on again — a return or a resale — tell the carrier exactly what is inside, because the goods may not travel on a passenger aircraft. If you reuse the box for something else, peel off or completely black out the old label: the ICAO rules require inappropriate dangerous-goods labels and marks to be removed or obliterated.
What it does not promise
It does not promise the parcel will fly at all, or that any carrier or postal service accepts it. It is not a hazard label and does not say what the danger is — the class label next to it does that.
A mark on a parcel is the sender’s statement about what is inside and how it should be handled. It is not a certificate that the parcel is packed safely, that anyone handled it as marked, or that your carrier accepts it: for what you may send, read the carrier’s own terms.
- What it looks like
- An orange rectangle printed in black with the words “CARGO AIRCRAFT ONLY”. The US rules fix black on an orange background, at least 110 mm high by 120 mm wide, with the words at least 6.3 mm high. The regulation’s own figure sets the rest of the layout; our drawing shows only the elements its text names and does not copy that figure.
- Regulation
- 49 CFR § 172.448 (the label), § 172.402(c) (when it is required) and § 172.407(c)(2) (its size); ICAO Technical Instructions, Packing Instruction 965
- Kind of mark
- An air-cargo mark: it applies when the package travels by aircraft, under the ICAO Technical Instructions and, in the United States, 49 CFR. It sits beside the dangerous-goods marks and labels rather than replacing them.
- Also called
- CAO label; CAO sticker; Cargo aircraft only sticker
What the rules say
Each person who offers for transportation or transports by aircraft a package containing a hazardous material which is authorized on cargo aircraft only shall label the package with a CARGO AIRCRAFT ONLY label specified in § 172.448 of this subpart.
— 49 CFR § 172.402 Additional labeling requirements — paragraph (c) Cargo Aircraft Only label, eCFR, Office of the Federal Register (US Code of Federal Regulations, current text). Checked 2026-10-12.The CARGO AIRCRAFT ONLY label must be black on an orange background.
— 49 CFR § 172.448 CARGO AIRCRAFT ONLY label, eCFR, Office of the Federal Register (US Code of Federal Regulations, current text). Checked 2026-10-12.The CARGO AIRCRAFT ONLY label must be a rectangle measuring at least 110 mm (4.3 inches) in height by 120 mm (4.7 inches) in width. The words “CARGO AIRCRAFT ONLY” must be shown in letters measuring at least 6.3 mm (0.25 inches) in height.
— 49 CFR § 172.407 Label specifications — paragraph (c)(2), size of the CARGO AIRCRAFT ONLY label, eCFR, Office of the Federal Register (US Code of Federal Regulations, current text). Checked 2026-10-12.amend “Passenger and cargo aircraft for UN 3480” to read “Cargo aircraft only for UN 3480”
— Doc 9284-AN/905, 2015–2016 Edition, Addendum No. 4: UN 3480 lithium ion batteries made cargo aircraft only, ICAO (Doc 9284, Technical Instructions for the Safe Transport of Dangerous Goods by Air). Checked 2026-10-12.the cargo aircraft only label must be located on the same surface of the package near the lithium battery mark, if the package dimensions are adequate.
— DGP/26 report, Appendix B: amendments to the ICAO Technical Instructions including Packing Instruction 965 and the panel’s discussion of the cargo aircraft only label, ICAO Dangerous Goods Panel (DGP/26-WP/3, report and amendments to the Technical Instructions). Checked 2026-10-12.
Related
Other air-cargo marks
Sources
Each document was fetched and read on the date shown. Written in our own words; quotations are the documents’ wording.
- Regulation, official text — eCFR, Office of the Federal Register (US Code of Federal Regulations, current text): 49 CFR § 172.402 Additional labeling requirements — paragraph (c) Cargo Aircraft Only label — Paragraph (c): a package of hazardous material authorised on cargo aircraft only must carry the CARGO AIRCRAFT ONLY label of § 172.448, applied by whoever offers or transports it by aircraft. Checked 2026-10-12.
- Regulation, official text — eCFR, Office of the Federal Register (US Code of Federal Regulations, current text): 49 CFR § 172.448 CARGO AIRCRAFT ONLY label — The label’s figure (an image in the regulation, not reproduced here) and paragraph (b): black on an orange background. Checked 2026-10-12.
- Regulation, official text — eCFR, Office of the Federal Register (US Code of Federal Regulations, current text): 49 CFR § 172.407 Label specifications — paragraph (c)(2), size of the CARGO AIRCRAFT ONLY label — Paragraph (c)(2): a rectangle at least 110 mm high by 120 mm wide, the words CARGO AIRCRAFT ONLY at least 6.3 mm high; the same section gives the orange as PANTONE 151 U. Checked 2026-10-12.
- ICAO document — ICAO (Doc 9284, Technical Instructions for the Safe Transport of Dangerous Goods by Air): Doc 9284-AN/905, 2015–2016 Edition, Addendum No. 4: UN 3480 lithium ion batteries made cargo aircraft only — Packing Instruction 965 heading changed from “Passenger and cargo aircraft” to “Cargo aircraft only” for UN 3480, passenger-aircraft quantities changed to “Forbidden”, and the cargo aircraft only label added to the packages’ labelling. Checked 2026-10-12.
- ICAO document — ICAO Dangerous Goods Panel (DGP/26-WP/3, report and amendments to the Technical Instructions): DGP/26 report, Appendix B: amendments to the ICAO Technical Instructions including Packing Instruction 965 and the panel’s discussion of the cargo aircraft only label — Packing Instruction 965 text placing the cargo aircraft only label near the lithium battery mark; the panel calling the label a critical measure against loading on passenger aircraft; the road-segment remark; and the shipper requirement (5;1.1 h) to remove or obliterate inappropriate labels and marks. Checked 2026-10-12.