A document was published by the EU Commission on 13 November 2018 “Preparing for the withdrawal of the United Kingdom from the European Union on 30 March 2019: a Contingency Action Plan“.
The document was largely overlooked by commentators where their main focus was on the flurry of activity around finalising the Withdrawal Agreement and Political Declaration.
Today, 19 December 2018, the EU has published the final version of the original document fomally known as
COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE EUROPEAN COUNCIL, THE COUNCIL, THE EUROPEAN CENTRAL BANK, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE, THE COMMITTEE OF THE REGIONS AND THE EUROPEAN INVESTMENT BANK
Preparing for the withdrawal of the United Kingdom from the European Union on 30 March 2019: a Contingency Action Plan
In addition they have also published a Q&A document
Questions and Answers: the consequences of the United Kingdom leaving the European Union without a ratified Withdrawal Agreement (no deal Brexit)
Copies of these documents are also available here
Points of note
It appears that these contingency measures will not apply to Gibralatar
By virtue of Article 355(3) TFEU and to the extent provided for in the 1972 Act of Accession of the United Kingdom to the European Communities, Union law applies to Gibraltar as a European territory for whose external relations a Member State is responsible. Article 355(3) TFEU will no longer apply to Gibraltar when the United Kingdom is no longer a Member State. As a consequence, contingency measures will not apply to Gibraltar.
Does the EU intend to close their border with Gibraltar?
No visa requirements for UK citizens visiting EU countries (for up to 90 days in a 180 day period)
For short stays (up to 90 days in a 180 day-period) the Commission has adopted a proposal for a Regulation13 which exempts UK nationals from visa requirements, provided that all Union citizens are equally exempted from UK visa requirements.
Proposals to avoid full interruption of air traffic to and from the UK
A proposal for a Regulation to ensure temporarily, for 12 months, the provision of certain air services between the United Kingdom and the EU27 Member States, allowing air carriers from the United Kingdom to fly across the territory of the Union without landing, make stops in the territory of the Union for non-traffic purposes, and perform scheduled and non-scheduled international passenger and cargo air transport services. This is subject to the United Kingdom conferring equivalent rights to air from the Union, as well as to the United Kingdom ensuring conditions of fair competition.
A proposal for a Regulation regarding aviation safety to extend temporarily, for 9 months, the validity of certain existing licences, to address the specific situation in the aviation safety sector where the European Union Aviation Safety Agency (EASA) can only issue certain certificates on the basis of a licence issued in a third country, while the United Kingdom can only issue licences as of the withdrawal date, when it has re-gained the status of “State of design”.
Further details can be found in the referenced document.