One of the stranger and bolder pieces of US legislation slipped into force in November 2012 – The European Union Emissions Trading Scheme Prohibition Act of 2011 - sic. This enables the US Secretary of Transportation to prohibit US airlines from complying with EU rules. Those EU rules apply to all airliners which touch down or take off in the EU, and requires them to participate in the EU Emissions Trading Scheme – designed progressively to limit carbon emissions from aviation via a cap and trade mechanism.
The US Act would be odd enough in its lack of respect for the laws of other countries, had the Act’s beneficiaries (the US airlines) not sought to challenge the legality of the EU measure in the EU Courts – and failed: see my post on the judgment of the CJEU. As will be seen, the EU Court expressly rejected claims (by US airlines) that the rules had extra-territorial effect and conflicted with international aviation conventions. Hence, the scheme was lawfully applicable to US airlines – just as to those of all other countries using EU airports.