Fossil-based fuels are commonly used in aircraft engines but they have a polluting effect and they cause a greenhouse effect for our world. This study reports a research about aircraft gas turbine engines which are fired by liquid hydrogen (LH2) in terms of performance and environmental aspects. Also, the performance and emissions of LH2 fueled engines are compared with those of kerosene fired aircraft engines. Same flights from Istanbul to London, and Paris to Kabul are examined to estimate the emission from a conventional aircraft as an application in aviation sector. It is shown that the amount of NOx, HC and CO emissions for traveling by a conventional aircraft for London is 78.36, 1.202 and 22.4 kg, while Paris is 71.55, 1.171 and 21.63 kg, and Kabul is 111.44, 1.36 and 26.11 kg, respectively. For the use of liquid hydrogen as a fuel, amount of gas emissions decreases for any destination like London, Paris and Kabul. Total HC and CO emissions are going to be nearly 0 kg because of lack of carbon in the fuel. Also NOx emission is lower because of wider flammability limit of LH2. Results show that the aircraft engines with LH2 have great potential for emissions reduction and engine performance parameters are a little better for LH2 fuel. It is strongly emphasized that one of the most important advantages for the use of LH2 is national independence for fuel supply. Oil cannot be extracted in every countries territory but LH2 is producible for every country and this is so important for a countries freedom. (C) 2012 Elsevier Ltd. All rights reserved.