Delta has four A220-100 (CS100) aircraft as of Jan. 2, 2018. Delta A220-100's are configured for short field/hot-and-high performance, equipped with PW1524G each rated at 24,400 Ibs. of takeoff thrust. The weight (134,000 Ibs.) to total thrust (48,800 Ibs.) ratio is 2.754:1. You may have heard Swiss and Air Baltic rave about the A220/CSeries incredible fuel efficiency, but what is not well-known is that the plane is a monster and has the best power-to-weight ratio of any mainline aircraft. You can look up some cockpit videos in addition to the YouTube videos posted by passengers in the links listed below.
Acceleration of an A220 from London City to Vr 132 knots (152 mph) takes 16 seconds:
The MTOW takeoff field length is 4,800 feet for the A220-100, and 6,200 feet for the A220-300. The aircraft has so much excess takeoff and climb thrust at full throttle, that the nose attitude must be held up at more than 25 degrees to keep its airspeed in check:
An inflight video of the cockpit reveals fuel efficiency of the CS300:
According to the engine displays shown at 7:42, the A220-300 burns a total of 3564 Ibs.per hour (or 810 kg/hr per engine) at Mach .78