I started to develop my corpus by downloading articles on air travel from internet tourism magazines. As tourism is a rather wide issue I had to encompass a narrower scope and focused on travel by air. I assumed that analysing a reliable amount of data with the help of frequency ranges would help me with the selection of the most appropriate vocabulary items to be tested. The amount of data proved to be a crucial point of my investigation. I tried to find evidence to support my hypothesis that with a representative amount of data I would be able to select the most important and most frequent words of a specialised lexis in specialised texts. Thus I have collected twenty-six carefully selected professional articles from different websites comprising approximately thirteen thousand tokens.