进出口贸易中的运输单据是承运人收到承运货物签发给出口商的证明文件，它是交接货物、处理索赔与理赔以及向银行结算货款或进行议付的重要单据。在国际货物运输中，运输单据的种类很多，其中包括海运提单、铁路运单、承运货物收据、航空运单和邮包收据等，现就航空运单进行一定了解，具体如下：

航空运单（Air Waybill，简称AWB）是承运人与托运人之间签订的运输契约，也是承运人或其代理人签发的货物收据。航空运单不仅应有承运人或其代理人签字，还必须有托运人签字。航空运单与铁路运单一样，不是物权凭证，不能凭以提取货物，必须作成记名抬头，不能背书转让。收货人凭航空公司的到货通知单和有关证明提货。航空运单正本一式三份，分别交托运人航空公司和随机带交收货人，副本若干份由航空公司按规定分发。

An air waybill (AWB) or air consignment note is a receipt issued by an international airline for goods and an evidence of the contract of carriage, it is a document of title to the goods. Hence, the air waybill is non-negotiable. The air waybill is the most important document issued by a carrier either directly or through its authorized agent. It is a non-negotiable transport document that covers the transport of cargo from airport to airport. By accepting a shipment, an IATA cargo agent is acting on behalf of the carrier whose air waybill is issued. Air waybills have eleven digit numbers which can be used to make bookings, check the status of delivery, and a current position of the shipment. Air waybills are issued in eight sets of different colors. The first three copies are classified as originals. The first original, green in colour, is the issuing carrier's copy. The second, coloured pink, is the consignee's copy. The third, coloured blue, is the shipper's copy. A fourth brown copy acts as the Delivery Receipt or proof of delivery. The other four copies are white.

航空运单主要分为两大类，具体内容如下：

1.航空主运单（MAWB，Master Air Waybill）

凡由航空运输公司签发的航空运单就称为主运单。它是航空运输公司据以办理货物运输和交付的依据，是航空公司和托运人订立的运输合同，每一批航空运输的货物都有自己相对应的航空主运单。

Master air waybill (MAWB) is a transport document, which is used in air shipments, issued and signed by the air cargo carrier or its agent, generally on a pre-printed carrier's air waybill format, evidences the terms and conditions of the carriage of goods over routes of the carrier(s). Master waybills can also be identified as an airline air waybills, with pre-printed issuing carrier identification.

2.航空分运单（HAWB，House Air Waybill）

集中托运人在办理集中托运业务时签发的航空运单被称作航空分运单。在集中托运的情况下，除了航空运输公司签发主运单外，集中托运人还要签发航空分运单。

House air waybill (HAWB) is a transport document, which is used in air shipments, issued and signed by a freight forwarder, generally on a natural air waybill format, evidences the terms and conditions of the carriage of goods as specified by the freight forwarder. Neutral air waybills, without pre-printed identification of the issuing carrier can be used to issuance of house air waybills.

在这中间，航空分运单作为集中托运人与托运人之间的货物运输合同，合同双方分别为货A、B和集中托运人；而航空主运单作为航空运输公司与集中托运人之间的货物运输合同，当事人则为集中托运人和航空运输公司。货主与航空运输公司没有直接的契约关系。不仅如此，由于在起运地货物由集中托运人将货物交付航空运输公司，在目的地由集中托运人或其代理从航空运输公司处提取货物，再转交给收货人，因而货主与航空运输公司也没有直接的货物交接关系。以下为相关例句，供参考，以加深对上述术语的理解：

例句1

An air waybill is a contract—an agreement enforceable by commercial law. To become a valid contract it has to be signed by the shipper or his agent and by the carrier or its authorized agent. Although the same individual or organisation may act on behalf of both the carrier and the shipper, the air waybill must be signed twice one each in the respective carrier and shipper boxes. Both signatures may be of the same person. This also implies that the air waybill should be issued immediately upon receipt of the goods and letter in instructions from the shipper.

航空运单是一份合同—一份可由商法强制执行的协议。若要成为有效的合同，必须由托运人或其代理人及承运人或其授权代理人签署。尽管相同个人或机构可以代表承运人及托运人行事，但航空运单必须签署两次，分别置于承运人及托运人各自的包装箱内。两个签名可以是同一个人。这也意味着航空运单应在收到货物及托运人的指示书后立即签发。