Compression stockings have beneficial effects on the development of venous thromboembolic complications and oedema during long- haul flights. A randomized controlled trial investigating the effect of compression stockings during short-haul flights with a duration less than fur ours is lacking. Deep vein thrombosis is very rare on flights shorter than four hours, but compression stocking could have beneficial effects on other outcomes. The aim of this study is to assess if compression stockings used during a 3-3.5-hour flight will decrease leg edema and discomfort.

All participants will be adults who will undergo a 3-3.5 hours flight. Participants have received oral and written information about the trial. All compression stockings have a class two compression level (corresponding to 23-32 mmHg compression). Participants will be randomized to wear a compression stocking on one leg, while the other side acts as control. Within an hour preflight, the patient will measure ankle and calf circumference at marked circumferential areas on the leg and answer questionnaires regarding leg pain and subjective discomfort, whereafter the stocking will be put on, on the randomized side. Within one hour after the flight the stocking will be removed and patients will once again measure the ankle and calf circumference at the marked circumference and fill out the questionnaire.

Sample size: Mean difference in ankle circumference set to -0.19 cm. Standard deviation of the mean difference set to 0.3, 5% alfa and 80% power. Sample size with a paired design = at least 18 participants. However, for practical reasons we will include up to approximately 50 adults in the trial.

Withdrawal and dropout criteria: All participants can withdraw their consent at any point during the trial, without the need for explaining any reasons for withdrawal. Since compression stockings do not cause side effects, except for patients with severe arterial insufficiency in the legs, we do not expect the trial to be stopped due to complications. All withdrawals will be accounted for in the scientific publication.

Inclusion Criteria:

• Adult participants ≥ 18 years of both sexes. Otherwise no restriction, since each participant acts as their own control.

Exclusion Criteria:

• Any condition requiring compression stockings during short-haul flights. Severe arterial insufficiency in the lower extremities.

Outcomes will be self-reported, and the author that assesses the outcomes and performs data analyses will be blinded.