LOUISVILLE, Ky. (WDRB) -- More than 100 UPS aircraft mechanics and other support staff picketed Monday at the Amazon warehouse in Jeffersonville. 

Organizers said it was to let Amazon know about the problems the mechanics and maintenance workers are facing at UPS. Amazon is UPS's largest client, with the shipping giant handling 30 percent of Amazon's shipments.

The mechanics and maintenance workers protested proposed changes to their health benefits. The aircraft maintenance workers voted overwhelmingly to authorize a strike in November of 2016. Recently, more than 900 of the mechanics sent an open letter to UPS CEO David Abney and the board of directors, citing their concerns and letting them know that they will do whatever it takes to secure a fair contract. 

Some protesters carried signs displaying a copy of that letter.

UPS Airlines Strategic Communications Director, Mike Mangeot released a statement saying:

"UPS continues to negotiate in good faith for a win-win contract. This union activity is simply routine posturing aimed at influencing talks. The reality is, negotiations continue under the control of the National Mediation Board, with dates scheduled for several months to come. We remain confident that we will reach a mutually favorable agreement, just has we have in all previous mechanic negotiations."

The protest started at 9 a.m. and was scheduled to end at 1 p.m. 

A similar protest was held outside Amazon in October. 

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