Mitchell 
4K
Foreground: Delta Connection or similar US legacy regional; Background: US Government/Military or charter
B737 and CRJ series
Boeing (foreground: Bombardier/Canadair) Boeing 737 (background, likely 737-700 or 737-800); Bombardier CRJ (foreground, likely CRJ-900)
The presence of an all-white 737 with a US flag likely indicates a government, military, or charter use, not a civilian airline.