• Defunct airlines of the United States (31 C, 633 P, 1 F)
• Defunct public transport operators in the United States (4 C, 154 P)
• Defunct railroad companies of the United States (5 C, 11 P)
• Defunct shipping companies of the United States (9 C, 188 P)

K

• Kellogg Transportation Company (4 P)

O

• Oregon Railroad and Navigation Company (12 P)

P

• People's Transportation Company (23 P)

U

• Upper Willamette Transportation Line (3 P)

W

• Willamette River Transportation Company (4 P)
• Willamette Transportation Company (6 P)

A

• Alaska Syndicate
• Atlantic Express (bus company)
• Atlantic Greyhound Lines

C

• Callendar Navigation Company
• Capitol Greyhound Lines
• Central Greyhound Lines
• Chariot (company)

D

• Dixie Greyhound Lines

F

• Flexcar
• Florida Greyhound Lines
• Flytenow

G

• Gettysburg and Petersburg Turnpike Company
• Great Lakes Greyhound Lines
• Grey Rabbit

M

• Minnesota Stage Company

N

• North Pacific Steamship Company

O

• Oregon Railroad and Navigation Company
• Oregon Steam Navigation Company

P

• People's Transportation Company

R

• Red Ball Transportation Company

S

• Southeastern Greyhound Lines
• Streckfus Steamers
• Summon (company)

T

• Teche Greyhound Lines
• Tennessee Coach Company
• Travana

U

• Upper Willamette Transportation Line

W

• Willamette Transportation Company

Y

• Yellow Corporation