Expansion in air and biomass operations have fuelled higher half-year profits at road and rail haulier Stobart Group.Stobart, which owns Southend airport in Essex, said the launch of a fourth home-based easyJet aircraft there helped to increase passenger numbers to 528,000, up 43% from the same time a year ago.Meanwhile, biomass tonnages increased 52% to 354,000 against a year ago and three major supply deals had been signed.Underlying profit before tax rose to £13.8m from £13.1m a year earlier on revenue from continuing operations of £330.2m against £247.4m in 2012.The group made improvements and savings in its vehicle logistics business by investing in new vehicles and closing its head office. The group also made £25m from property sales and said it had made another disposal in the second half.Chief Executive Andrew Tinkler said: "We are on track to deliver value across all of our divisions in line with our strategy. Our market-leading transport business continues to perform well and our growing air and biomass divisions are beginning to deliver on their potential."PW