Dispersal plays a key role in shaping biological properties underlying various ecological processes, such as the distribution, dynamics and viability of spatially-structured populations or the pace and scale of pest invasions. For spiders (ballooning) and plants (anemochory), aeronautic dispersal comprises the main mode of long distance movements. During the process of this dispersal event, organisms are carried by wind currents as spheres attached to thin silk threads or to specific seed structures (pappus). For these, biomechanical models predict distances covered by objects with similar masses and shape to be primarily determined by respectively thread or pappus length. Consequently, investments in dispersal can be quantified by behavioural traits (tiptoe behaviour in spiders, mobility protocols) or by morphological traits (seed and pappus structure in plants). Relationships with environmental (landscape factors, population characteristics, stress), maternal and genetic factors are studied in laboratory experiments and through field observations. For arthropods, syndromal relationships with other behaviours related to settling; for e.g. web-building (read more), host plant selection are studied. Trade-offs with seedling establishment are studied in anemochorous plants. Although wind-borne dispersal comprises the main focus of this research, landscape-dependent variation in mobility or dispersal are also addressed; for e.g., other passive dispersal modes like floating (read more), hitchhiking dispersal and general mobility in spiders, grasshoppers and butterflies.