My husband and I am planning to go to India in September. He has reapplied for his green card and got a extention letter in the mail.

I assume that when you say that your husband got an extension letter in the mail, that was through an application to remove the conditions of residence status. In such case, he should be able to safely travel with his expired green card and the extension letter. I do note that there are some countries whose immigration authorities do not recognize the extension letter, and to be safe, some individuals obtain an I-551 temporary stamp of permanent residence in their passports from the local U.S.C.I.S. field office before making a trip. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.