M&A speculation and contract wins from the Farnborough Air Show were helping stocks in the aerospace and defence sector post solid gains on Wednesday.Aircraft components manufacturer and engineering group Meggitt was the standout performer in afternoon trade, up nearly 10% at 537p on the back of reports that the company is a potential bid target.The FTSE 100 group, which makes parts for the Boeing 787 Dreamliner, is said to have attracted the attention of US group United Technologies.According to the Daily Mail, which cited rumours emanating from Farnborough, the US firm could offer as much as 625p a share for Meggitt, a 28% premium to Tuesday's closing price of 490.1p.Engine maker Rolls-Royce was also rising strongly today, up over 2%, as the company continues to report contract wins following the Farnborough event. Since the start of the week alone, the company has already announced orders from Kuwait Airlines, Air Lease Corporation, Airbus, CIT, Avolon, AirAsia X and MG Aviation.Anti-missile flare producer Chemring was up nearly 3% today. Its new Chief Executive Michael Flowers told ShareCast in an interview yesterday that while defence markets are still difficult, signs of growth are emerging.Others in the sector including Ultra Electronics, Senior, Cobham and BAE Systems were also on the rise today.Top performing sectors so far todayAerospace and Defence 4,947.35 +2.48%Mining 17,772.50 +2.46%Technology Hardware & Equipment 1,035.27 +2.44%Forestry & Paper 11,385.33 +2.42%Industrial Metals & Mining 1,248.60 +2.15%Bottom performing sectors so far todayIndustrial Transportation 2,931.03 -0.49%Tobacco 39,924.73 -0.37%Pharmaceuticals & Biotechnology 13,248.17 -0.09%BC