The Unite Union is calling for action to save 240 jobs at Marshall in Cambridge.
Unite are asking the city's MP Julian Huppert to put pressure on his Liberal Democrat colleague, the Business Secretary Vince Cable, to support Marshall.
Up to 240 jobs are under threat at the company's aerospace and defence divisions, and at the company's site in Mildenhall.
Marshall is Cambridge's biggest private employer, but has been hit by a decline in Ministry of Defence contracts.
Unite say the threat of job losses is particularly hard on workers in the run up to Christmas.
“Cambridge can’t afford to lose these skilled engineering jobs – the city needs a balanced economy and can’t rely on the two universities, Addenbrooke’s hospital and the companies operating in Silicon Fen. It also needs a strong manufacturing and engineering base.
“Unite will be fighting very hard to retain as many jobs as possible at Marshall in the days and weeks ahead.”
American F-15 fighters normally based at RAF Lakenheath in Suffolk have been moved to the nearby airbase at Mildenhall while runway repairs are carried out.
From September 13th, 12 of the all-weather tactical fighters will be based at Mildenhall for two and a half weeks. The USAF say a minimal number of missions will be flown unless they are absolutely essential and Mildenhall's noise restrictions will be applied.
Police in Suffolk have issued a picture of jewellery stolen in a burglary in Mildenhall.
The raid happened some time on Sunday night into the early hours of Monday when a wallet and jewellery was stolen from the front room.
The items stolen were a gold wedding band with "Forever J" engraved inside, a gold ring with a heart shaped ruby and diamonds either side, a gold necklace with a cross, a white gold engagement ring with a diamond and a man’s leather wallet and contents.
Anyone with information about the burglary should contact Suffolk Police on 101 or call Crimestoppers on 0800 555 111.
A tradesman unwittingly sparked a security alert at a US Air Force base in Suffolk. The main gate at RAF Mildenhall was closed for more than two hours after a sniffer dog alerted security staff about a van entering the base.
It is thought an old munitions case being used as a toolbox in the van might have been to blame. After a search the van was declared safe.
The family of an airman killed in a collision outside Newmarket in Suffolk have paid tribute to him.
Staff Sgt Anderson Johnson was stationed at RAF Mildenhall with the 100th Civil Engineer Squadron. The 24-year-old from Texas was killed when his car crashed into a tree at about 2am on July 28.
In a statement his family said he had a smile "like the sun". They said "his laughter was contagious and his cheek bones reached the clouds... He was a wonderful husband, son, brother, family member... We want to thank all of you for taking care of him and loving him while he was with you."
Johnson is survived by his wife, Markeah Johnson, his parents, Anderson Johnson III and Margarita Tedder, and his siblings Tashica Johnson and Dominque Tedder.