I don’t know but online I saw that their flight was delayed because his sis-in-law got delayed at work. So they got started late and then they all were ... “late” (flying over ocean at night, inexperienced). It was get-there-itis...he could have quickly flown in the next morning but...
When Camille Paglia still had her Salon column (oh, how I miss it!) she related that she was near the little airport that night when he departed. She was having dinner with her family. She wrote about the fog and was shocked out of her wits when she found out he flew that night.