Sean O’Keefe, 54, and his 17-year-old son Jonathan both survived the crash which occurred on Monday night in a remote part of Alaska. However, former Alaska senator Ted Stevens died in the crash.
Mr O’Keefe and his son are believed to have suffered multiple injuries and are being treated in an Alaskan hospital.
“I think Sean has a broken pelvis and a lot of scrapes and burns. Jonathan has a broken leg and other lacerations and some burns,” a contact of the family said.
The party-of-nine was on a fishing trip in a remote part of the state.
Mr O’Keefe worked for Mr Stevens for many years in Congress on annual spending matters, including defence.
In 2001, he was appointed top administrator at NASA by former US President George W Bush.
In March 2003 and 2004, he was recognised and honoured by the Irish American Magazine as one of the top 100 Irish Americans. His time in charge at NASA saw the death of seven astronauts following the destruction of the space shuttle Columbia.
Mr O’Keefe is chief executive of EADS North America, helping oversee the aerospace giant’s efforts to win the Pentagon’s $35 billion (€26bn) contract to build the next generation of aerial refuellers against rival Boeing. He lives in Virginia with his wife and three children.
Mr Stevens, a Republican, was a former chairman of the powerful Senate Appropriations Committee and a strong supporter of robust US defence budgets.