The majority of patients presenting with differentiated thyroid cancer have early small disease with excellent long-term outcomes. However, aerodigestive tract invasion is reported in around 10% of case series and is a poor prognostic factor. This article has been authored by members of the International Head and Neck Scientific Group (IHNSG) and reviews the patterns of invasion and provides a clear management strategy. Salient points in the history and examination are highlighted and the use of appropriate radiological imaging is discussed concisely. The Czaja and Shin classification systems for staging the extent of airway involvement are presented and are of use in determining the extent of resection required. The surgical aim is to resect all gross disease. In cases of early superficial visceral invasion, ‘shave’ procedures are recommended. When transmural invasion of the trachea or oesophagus is encountered, full thickness excision is necessitated. The extent of resection in intermediate cases, where the invasion has extended beyond the superficial layers, but has not reached the submucosa, is controversial and the current consensus is for less radical surgery. The use of external beam radiotherapy in radioactive iodine resistant tumours should be considered by the multi-disciplinary team.