FedEx and the United Parcel Service have added thousands of seasonal employees and rental vehicles ahead of a holiday shopping season that's expected to break records with another increase in online shopping.

FedEx has moved into high gear by hiring 50,000 seasonal employees including drivers, package handlers, helpers, and other support positions. UPS has added 95,000 additional employees as well as several thousand rental vehicles including package cars, tractors and shifting units.

This year, UPS has been outfitting 47 new and expanded facilities. About 15 locations will have modular units such as loading doors and connected conveyors to expand capacity. Each of these "mobile delivery villages" can dispatch between 60 and 90 vehicles.

Industry experts at comScore have predicted a 16 percent increase in web sales to $61 billion, including a 25 percent increase in sales from mobile devices. Adobe predicted online sales for Thanksgiving Day itself to rise 27 percent to $1.35 billion, with 31 percent of those sales being made from a smart phone or tablet. That's up from 21 percent last year.

FedEx expects to move more than 290 million shipments between Black Friday and Christmas Eve, an 8.8 percent increase in overall year-over-year peak seasonal volume, according to a FedEx release.

UPS expects Dec. 22 to be its peak day and forecasts it will deliver 34 million packages that day. UPS delivers 17 million packages on an average day, according to the company.