American officials said they haven't seen the suits and could not comment.
Passengers were deprived of medication and "suffered hunger, thirst, anxiety, physical illness, emotional distress and monetary loss," according to the lawsuits.
"The toilets became full and would not flush, and the stench of human excrement and body odor filled the plane," Ray's suit alleges.
The lawsuits ask for unspecified damages as well as legal expenses.
Both suits were filed in circuit courts; Hanni's in California and Ray's in Arkansas. They seek class-action status, claiming the airline's decisions affected 12,000 passengers that day.
The flights were among hundreds diverted when an unusual system of storms snarled traffic over the airport.
"A major weather event that no one predicted" happened and caused 119 flights to be diverted that day, the most since 9/11, said airline spokesman John Hotard.
The airline has worked to improve its system for dealing with severe weather, having installed new software for tracking diverted flights and now permit passengers to leave planes after four hours if safety allows, Hotard said.
Hanni was inspired to create a passenger-rights group and has lobbied Congress to pass an "airline passenger's bill of rights" that would guarantee minimum service levels for air travelers. No bill has yet been passed.
