[2] An avid pilot in private life, Dr. Mitchell re-enlisted in the Navy in 1951, and served as a Naval Flight Instructor in Pensacola, Florida, from 1951–1953, during the Korean War.

And in 1974, Mitchell led another successful campaign to prevent the Air Force from cutting 1,500 jobs at the Rome Air Development Center at Griffiss Air Force Base in Rome, NY[6] In 1982, at the behest of Broadway Producer Joe Papp, and with the encouragement of members of his family and others involved in a "Save the Theatres"[7][8][9][10] effort to preserve historic Broadway theatres in New York City, Mitchell introduced legislation in the Congress along with 13 co-sponsors[b] to designate a "Broadway/Times Square Theatre District National Historic Site" in Mid-Town Manhattan.

[c] Mitchell's bill (97th Congress – H.R.6885) faced fierce opposition and extensive lobbying mounted against it by Mayor Ed Koch's administration and big-money Manhattan development interests.

Although the measure was, consequently, never enacted – the overall effect of his legislative initiative and of the "Save the Theatres" effort generally, however, was to slow down the rapid destruction of the old Theater District.

[12] As a result in large part to Papp's efforts, with the support of Congressman Mitchell and many others, the Theater District remains one of New York City's primary and most popular tourist attractions and destinations.

There he resumed his optometry practice, he and his wife Gretta dividing their time between homes in the Mohawk Valley and in Cedar Key, Florida.

The foundation and the Mitchell fund's mission is to build partnerships, inspire leadership and generate positive outcomes toward increasing the percentage of adults with bachelor's degrees in Herkimer and Oneida counties, through annual grants to local students; and to embrace other programs and collaborations that address economic development, education, health, and arts and culture in the region.

"[1] Escorted by both Active Duty, and American Legion Veterans honor guards – and borne by uniform personnel representing all branches of the U.S. Military – Mitchell was interred with full military honors, accompanied by "Taps" and the firing of volley shots, on a hillside at the Oak Hill Cemetery overlooking a tributary of the Mohawk River in his hometown of Herkimer, New York.