Mr Ulrich, 52, was listed as the pilot but it is not known who was flying at the time of the plane's disappearance, Mr Kelly said.
Blumin has been featured in numerous media outlets that profiled the Skylight Group, which she founded in 2004. According to the Coast Guard, there was no "significant adverse weather" at the time, and Ulrich is considered an experienced pilot.
He said a search plane and patrol boat have been searching 3,400 square miles since Monday but that that radius has since been expanded. No bodies or survivors have been found.
She indicates that if something did indeed happen, the mishap was nearly certainly a result of an equipment malfunction on the plane.
A Coast Guard cutter was dispatched to the area and is expected to arrive later today to arrive with the search.
Through the night an Air Force AC-144, a C-130 and an HH-60 helicopter were also involved in the hunt for the missing plane.
Ramsey is a Manhattan architect and principal of the design studio Raad.
A New Hampshire man, a New York City mom and two toddlers are feared lost in a plane crash near the Bermuda Triangle. Ramsey, creator of the proposed Lowline underground park, is the father of the two toddlers.
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The pair have two sons together, four-year-old Phineas and two-year-old Theodore.
PHOTOS: Help Find America's Missing Children! Results from their evaluation indicated that the MU-2B model, along with its peers in the MU-2 class, did indeed meet all safety requirements, and that the plane was as safe as it could be when handled by properly trained pilots.
"What very bad, unthinkable, heartbreaking news", wrote another.
Reports claim that Ulrich's parents only found out about the plane's disappearance after a reporter called them to follow up for a story.
We were devastated and shocked to learn that Nathan, Jennifer and her children have been missing since leaving from Puerto Rico on Monday.
"Nathan is our beloved son, brother and uncle and we wish for resolution as the Coast Guard search continues", the Ulrich family statement said.
NY businesswoman Jennifer Blumin headed to Puerto Rico over Mother's Day weekend for what she thought would be a relaxing vacation with her family.