Aerospace and defence engineer Senior said strong order books at Airbus and Boeing had helped it keep profits on track since early July, but warned it was still facing high costs and government defence cuts.Senior said adjusted pre-tax profit since July 1st was in line with its expectations and net debt at the end of September had fallen to £61m, £10m lower than at the start of the year.Senior, whose aerospace activities make up 64% of its business, said the large commercial aircraft market remained "healthy", with Airbus and Boeing delivering a combined 921 aircraft in the first nine months of 2013 - nearly a tenth up on the 841 deliveries in the same period of 2012."Their resultant order books, in excess of eight years at current build rates, continue to provide a very strong foundation for future growth," Senior said.But it added: "Customer price pressure in the commercial aerospace sector remains on-going and is being managed in line with expectations."Overall business and regional jet markets stayed relatively weak, whilst reduced government spending and political indecision, particularly in North America, continued to hit the group's military and defence volumes."To date, these impacts have been largely as planned and have been appropriately managed, with the group's North American operation that supplies Sikorsky with Black Hawk helicopter parts most affected."It said its flexonics Division faced weaker demand in the North American heavy-duty diesel engine market, where customers reduced stocks as the anticipated market recovery did not materialise. Demand for passenger vehicles in Europe and India also stayed weak.