Combining Multiple Relation
You might have seen Passing Multiple Relation Criteria  in the docs

{% set entries = craft.entries.section('flightcompany').relatedTo([
    'and',
    { targetElement: models, field: 'partsModels.model' },
    { targetElement: parts, field: 'partsModels.part' }
]).all() %}


You can as well take a look at the Db::parseParam the and|or syntax is the same for this field