For small envelopes or packets attached to the air waybill, use Freight Attached Consignment.
Any consignment attached to the Air Waybill is known as Freight Attached Consignment (FAC). These consignments are so small that they cannot be transported separately. These are attached to the Air Waybills and put inside the CarGo pouch. The FAC generally constitutes of travel documents /tender documents/personal letters/passports/gift items etc.
How it travels
At IndiGo, we accept FAC and other small shipments on all our flights. At the same time, manifest and other operational documents (like Air Waybill copies) also get uplifted in the aircraft. There is a high chance of misrouting of the same. To avoid such incidents, the small shipments, FAC and the manifest and Air Waybill copies must be put inside a bag which is known as "Cargo Document bag".