Public opinion towards aviation generally is worsening , based on increasing environmental concerns relating to emissions and noise , and private flying has been criticised by respondents to a government consultation on aircraft noise as a frivolous or selfish activity . In terms of environmental complaints and enquiries made to the CAA that relate specifically to GA , noise is by far  the most common subject . Half of the 2 @,@ 000 noise complaints made annually to the CAA concern GA operations , most of which relate to aerobatics , helicopters using private sites , air balloon incidents , parachute dropping , and alleged low flying . Planning guidance on aircraft noise advises that in some circumstances the public perceive general aircraft noise levels as more disturbing than similar levels around major airports . This is a result of the tonal characteristics of light aircraft engines and the activities they are engaged in , including : repetitive circuit flying at low @-@ altitude near an aerodrome , during which aircraft are audible for long periods ; slow climbing aircraft engaged in parachute drop or glider tug activities concentrated around the drop zone or aerodrome , also audible for long periods ; erratic and repetitive engine noise from aircraft engaged in aerobatics ; and piston @-@ engines on full power in areas of low background noise , leading to the perception that such noise is more intrusive . In an attempt to alleviate these problems , the majority of aerodromes implement noise abatement procedures designed to route aircraft away from noise sensitive areas , and more than 50 are required by the government to provide consultative facilities in which local concerns can be raised with aerodrome operators . SMS Zrínyi SMS Zrínyi (  His Majesty 's ship Zrínyi  ) was a Radetzky @-@ class pre @-@ dreadnought battleship ( Schlachtschiff ) of the Austro @-@ Hungarian Navy ( K.u.K. Kriegsmarine ) , named for the Zrinski , a noble Croatian family . Zrínyi and her sisters , Erzherzog Franz Ferdinand and Radetzky , were the last pre @-@ dreadnoughts built by the Austro @-@ Hungarian Navy . During World War I , Zrínyi saw action in the Adriatic Sea . She served with the Second Division of the Austro @-@ Hungarian Navy 's battleships and shelled Senigallia as part of the bombardment of the key seaport of Ancona , Italy , during May 1915 . However , Allied control of the Strait of Otranto meant that the Austro @-@ Hungarian Navy was , for all intents and purposes , effectively bottled up in the Adriatic . Nonetheless , the presence of the Zrínyi and other battleships tied down a substantial force of Allied ships . With the war going against the Austrians by the end of 1918 , Zrínyi was prepared to be transferred to the new State of Slovenes , Croats and Serbs . On 10 November 1918 — just one day before the end of the war , navy officers sailed the battleship out of Pola ( Pula ) and eventually surrendered to a squadron of American submarine chasers . Following the handover to the United States Navy , she was briefly designated USS Zrínyi . In the Treaty of Saint @-@ Germain @-@ en @-@ Laye , the transfer was not recognized ; instead , Zrínyi was given to Italy and broken up for scrap . fill in the blank  : Public opinion towards aviation generally is worsening , based on increasing environmental concerns relating to emissions and __________________ , and private flying has been criticised by respondents to a government consultation on aircraft __________________ as a frivolous or selfish activity . 
Output:  noise