(Reuters) - U.S. companies aspiring to revive supersonic jet travel in the wake of Europe’s Concorde have built a business case around faster speeds for high-paying travelers, but face the challenge of reining in noise and emissions to meet new standards. [L4N1U506T]

FILE PHOTO: The Aerion AS2, the world's first supersonic business jet, being developed by Lockheed Martin Corp partnering with plane maker Aerion Corp of Reno, Nevada, is shown in this handout photo illustration released December 15, 2017. Aerion Corporation/Handout via REUTERS

Here is a list of the players:

AERION AS2

List price: $120 million

12-seat business jet

Cruise speed: Mach 1.4

Max range: 4,200 nautical miles

Engine: GE core used by F-16s and 737s

Entry into service target: Early 2026

Source: Aerion Supersonic

BOOM

List price: $200 million

55-seat commercial jet

Cruise speed: Mach 2.2

Max range: 4,500 nautical miles

Engine: Not yet selected

Entry into service target: Mid-2020s

Source: Boom Supersonic

SPIKE S-512

List price: $100 million

18-seat business jet

Cruise speed: Mach 1.6

Max range: 6,200 nautical miles

Engine: Not yet selected

Entry into service target: Mid-2020s

Source: Spike Aerospace

CONCORDE

100-seat commercial jet

Cruise speed: Mach 2

Max range: 3,600 nautical miles

Engine: Rolls-Royce/Snecma Olympus 593

Entry into service: 1976

Source: British Airways