UPS, FedEx Scramble to Shore Up Networks Drained By Deadly Crash

United Parcel Service Inc. and FedEx Corp. are working to secure enough freighters as they grapple with a ban on a pillar of their air-cargo fleets through the crucial holiday delivery season, and potentially beyond.

An indefinite grounding of the workhorse MD-11 jet is in place as investigators probe why an engine tore off a 34-year-old widebody just as it took off on Nov. 4. The resulting crash killed 14 people.

The grounding has drained capacity and complicated operations for the world’s largest package delivery companies just as shipping volumes surge for the peak period through Christmas. The crash also ...