(written from a Production point of view)
John D. Dixon is a stuntman, stunt actor, and stunt coordinator who served as stunt double for actor Tim Kelleher in the Star Trek: Enterprise episode "The Communicator". He received no credit for this appearance and his costume was sold off on the It's A Wrap! sale and auction on eBay. 
Dixon grew up on a ranch in Gilroy, California and was sure about his aim to be a stuntman at the age of seven. He trained stunts on the ranch and got his first stunt job on the live show "Midevil Times". Today he lives in Los Angeles, is married, and father of a son. Dixon has doubled for actors, including Chris Ellis, Jon Lovitz, and recently Steve Martin, in Pink Panther 2 (up for 2009).
Dixon has performed stunts in several television series, including Melrose Place, The Practice, Firefly, General Hospital, V.I.P. (1999, episode The Last Temptation of Val, with Brian Avery and Michael McFall), Charmed (2001-2006, coordinated by Noon Orsatti), Frasier (2002 starring Kelsey Grammer, and also as a stunt coordinator), Buffy the Vampire Slayer (2002-2003), CSI: Crime Scene Investigation (2003, episode Crash and Burn, with Wallace Langham, Christopher Leps, and Todd Slayton), J.J. Abrams' Alias (coordinated by Shauna Duggins), 24 (2006, coordinated by Jeff Cadiente, and with Gregory Itzin, Glenn Morshower, and Thom Williams), and Ghost Whisperer (2006, episode Free Fall, coordinated by Phil Culotta).
His feature film resume includes movies such as Naked Gun 33 1/3: The Final Insult (1994), Tim Burton's science fiction comedy Mars Attacks (1996, with Paul Winfield), Con Air (1997), the four time academy award nominated drama Armageddon (1998), Cheaper by the Dozen (2003), the sequel Tremors 4: The Legend Begins (2004, with Don Ruffin), the crime drama Gridiron Gang (2006, with The Rock and Leon Rippy), The Hitcher (2007), National Treasure: Book of Secrets (2007), the first and third installment of Pirates of the Caribbean(2003 and 2007, with Tom Morga and Brian Williams), and Steven Spielberg's upcoming sequel Indiana Jones and the Kingdom of the Crystal Skull (set for 2008, with Jon Braver, Kevin Derr, and Lauro Chartrand).