Dad's on a hunting trip and he hasn't been home in a few days is what Dean Winchester told Sam to get him to leave Stanford to hunt for their missing father. Versions of it have since been used by other hunters when someone goes missing and they need help.
|“||Dad's on a hunting trip and he hasn't been home in a few days.||”|
|“||Their mom's on a hunting trip and hasn't been home in a week.||”|
|“||Hi, Claire, it's Sam and Dean, they're missing. They were on a hunting trip and I haven't heard from them in a few days. It's time to come home.||”|
In Pilot, after their father goes missing, Dean travels to Stanford to enlist Sam's help in finding him. When Sam refuses to leave Jessica Moore to talk and doesn't get the urgency of what Dean is trying to explain to him, Dean tells Sam that "Dad's on a hunting trip and he hasn't been home in a few days." Finally understanding the urgency, Sam leaves Jessica behind in the apartment to hear Dean out. When he leaves, Sam makes up a lie for Jessica about Dean meant by what he said.
In Twigs & Twine & Tasha Banes, after Tasha Banes disappears, Sam tries to get Dean to agree to help Max and Alicia Banes look for her. When Dean is reluctant due to worry over Castiel, Sam tells him that "their mom's on a hunting trip and hasn't been home in a week." Though annoyed by Sam using his own words against him, Dean agrees to help the Banes family.
In Wayward Sisters, after the Winchesters get trapped in the Bad Place, a worried Jody Mills calls Claire Novak for help. Jody tells Claire that "they were on a hunting trip and I haven't heard from them in a few days. It's time to come home." Worried about her friends safety, Claire returns to Sioux Falls to help in the search.