Requirements:

Transport of Human Remains

1. Certified copies of Death certificate (2)
2. Burial/Transit Permit
3. Passport or birth certificate of decedent
4. Embalmer's affidavit      
5. Letter of non-contagious disease signed and notarized
6. License and Registration of Funeral Home
7. Funeral home letter stating: 1) only remains are inside the casket; 2) flight itinerary; 3) consignee's name, address, and telephone number;
8. Sealer Casket
9. Wood-bottom airtray

Consulates: http://www.state.gov/s/cpr/rls/fco/164201.htm#guyana

Embassy: http://guyanaembassyusa.com/