This article is part of a Special Issue on “Behavioural Epidemiology“. Mathematical modelling is an important public health tool for aiding the understanding of the spread of respiratory infectious diseases, such as influenza or COVID-19, and for quantifying the effects of behavioural interventions. However, such mathematical models rarely explicitly appeals to theories of human behaviour to justify model assumptions. Here, we propose a novel mathematical model of disease transmission via fomites (luggage trays) at airport security screening during an outbreak. Our model incorporates the self-protective behaviour of using hand sanitiser gel in line with the extended parallel processing model (EPPM) of behaviour. We find that changing assumptions of human behaviour in line with the EPPM gives qualitatively different results on the optimal placement of hand sanitiser gels within an airport compared to default modelling approaches with naïve behavioural assumptions. Specifically, that it is preferable to place hand sanitiser gels after luggage screening in most scenarios; however in situations where individuals perceive a high threat and low efficacy, this strategy may need to be reviewed. This situation of non-compliance is not addressed or captured in default models. Our model demonstrates how existing behavioural theories can be incorporated into mathematical models of infectious diseases.