Both, the bill of lading and airway bill are essential documents required at the time of an export transaction. However, they differ from each other.
A bill of lading is issued by a shipping company as a token of acceptance that the goods have been put on board of its vessel. A bill of lading is an undertaking by a shipping company to transfer the goods to the port of destination.
On the other hand, for goods sent through air, an airway bill is a written proof issued by airline companies. It is similar to bill of lading but is an undertaking by the airway company to transfer the goods to the airport of destination.