The aerospace and defence sector was in demand on Thursday afternoon with heavyweight constituents Rolls-Royce, BAE Systems and Meggitt providing a boost.Power systems group Rolls-Royce was trading 1.3% higher at 1,165p after winning a contract extension with the US Department of Defence to provide its 'MissionCare' services for the F405 (Adour) engines that power the US Navy's T-45 training aircraft. The extension, worth $50.7m to the FTSE 100 firm, continues the existing MissionCare support which has served the US Navy's training fleet over the past decade.Investors at defence contractor BAE Systems continue to celebrate the company's plans to cut 1,775 jobs at its shipbuilding yards in Scotland and England. The stock was up 1.6% at 462.9p.The move, announced on Wednesday, comes as BAE restructures its UK naval ships business after experiencing a "significant reduction in workload" following the peak of activity on the Queen Elizabeth Class Aircraft Carrier programme. The company is to consolidate its existing shipbuilding operations in Glasgow and invest in facilities to position itself for the anticipated Type 26 Global Combat Ships programme for the Royal Navy. BAE said that the cost of the restructuring will be borne by the Ministry of Defence.Meggitt, meanwhile, was rising 2% to 513.5p as sentiment recovers following a forecast downgrade which led to a sharp drop in the share price last week. The aerospace and defence manufacturer said on Friday that trading in the second half had been "slightly" below expectations and a supply hiccup could cost £20m. It now expects 2013 revenue growth rates to be in the "low single digits". It had given guidance of mid-single digit revenue growth for the full year at its interims in August. Top performing sectors so far todayIndustrial Metals & Mining 1,582.31 +3.61%Automobiles & Parts 8,800.48 +1.26%General Retailers 2,781.27 +1.23%Aerospace and Defence 5,244.52 +1.21%Insurance (non-life) 1,827.86 +0.79%Bottom performing sectors so far todayForestry & Paper 11,299.15 -1.96%Health Care Equipment & Services 4,468.31 -0.44%Gas, Water & Multiutilities 5,689.59 -0.35%Oil & Gas Producers 8,047.04 -0.26%Life Insurance 6,713.48 -0.24%BC