If the aircraft wasn't a military one, then it's likely that the owner was very wealthy, and probably has interests in engines, motorcars, and suchlike.
I knew there was a connection between Monmouth and Charles Rolls of Rolls-Royce cars fame, but have never studied his life, despite being keenly-interested in the superb RR aero engines his firm produced c1930 and afterwards. I now know that he was a keen enthusiast of early aviation, not at all surprising given his technical and wealthy background, especially in Edwardian times. I therefore wondered if the aeroplane that crashed at Wynol's Hill was on it's way to or from the Rolls ancestral home at The Hendre, Monmouth ?.

However, Charles Rolls had died long before the crash, in 1911. He has the sad distinction of being the first Briton killed in an aeroplane accident, during a display near Bournemouth, aged just 32. While studying mechanical engineering at Cambridge he'd travelled to Paris in 1896 to buy his first car, a Peugeot, one of the first three cars in Wales. At that time France were world-leaders in car technology, as she would be in aircraft a decade later. As well as creating motor cars with Henry Royce, Charles Rolls became interested in aviation, initially ballooning, making over 170 balloon ascents. He regularly hosted balloon events at Monmouth, see this family photograph by his balloon in 1906, the balloon is not a "modern" hot-air type, but gas-filled.
http://en.wikipedia.org/wiki/File:Ballooning_at_Monmouth_Gasworks.jpg

Flight Magazine of January 1909 reports a flight from Monmouth:
"Ballooning Home. On Saturday last the Hon. C. S. Rolls gave an exhibition of the possibilities of ballooning by taking his mother, Lady Llangattock, home by balloon. The ascent was made at Monmouth in the balloon " Mercury," the occupants of the basket being Lady Llangattock, Hon. C. S. Rolls, Hon. Mrs. Assheton – Harbord, Mr. Claud Crompton, and Mr. Charles Freeman, and the balloon landed on the lawn in front of Lord Llangattock's house, The Hendre."

Charles Rolls was a founding member of the Royal Aero Club in 1903 and was the second British person the Club licensed to fly. By 1907 his focus turned increasingly from cars to flying, he tried unsuccessfully to persuade Royce to design an aero engine. In 1909 he bought a Wright Flyer, an improved development of the world's first successful aeroplane of 1903, he made more than 200 flights. In 1910 he became the first man to make a non-stop double crossing of the English Channel by plane.

Sadly, soon after Charles was killed, the Rolls family name would die out. Charles' father 1st Baron Llangattock passed away in 1912. His older brothers both died in 1916, John from wounds on the Somme, Henry from illness. This left only mother Georgiana and sister Eleanor to see the end of WW1 hence the year of the aeroplane crash. So would they have entertained a visitor by aeroplane in 1918 ???. Mother Georgiana passed away in 1923 in their other home, in London, aged 86. However she may-well have been an aeroplane enthusiast - she was aged 72 when taking the aforementioned flight in 1906 !. Sister Eleanor also died in London, in 1961. At some point after 1916, and the end of the male Rolls line, The Hendre passed back up to the Harding-Rolls family who lived there until 1984.

So it rather seems that the Broadwell aeroplane was probably not enroute to visit the Rolls family, ah well...

Excellent articles about Charles Rolls here,
http://www.monnowvoice.co.uk/charles-stewart-rolls-1877-1910/
http://www.earlyaviators.com/erolls.htm

The Rolls family of Llangattock http://en.wikipedia.org/wiki/John_Rolls,_1st_Baron_Llangattock
http://en.wikipedia.org/wiki/The_Hendre

The 1891 Census for The Hendre, Monmouthshire, shows;

Given Name Surname Relationship Age Estimated Birth Year Gender Birth City Birth County Birth Country
John A Rolls Esq. Head(Independant gentleman) 54 1837 Male Llangattock Monmouthshire Wales
Gorgiana M Rolls Esq. Wife 53 1838 Female Kirkby O Blow Yorkshire England
John M Rolls Esq. Son 20 1871 Male Mayfair London England
Eleanor G Rolls Esq. Daughter 18 1873 Female Mayfair London England
Charles S Rolls Esq. Son 13 1878 Male Mayfair London England

Plus a further 21 staff including these Foresters,
George Wicks Servant 24 1867 Male Mathern Monmouthshire Wales
Henry Polly Servant 25 1866 Male Clearwell Gloucestershire England
Sarah Lewis Servant 20 1871 Female Ruardean Gloucestershire England
Louisa Long Servant 21 1870 Female Llanvihangel Yestern Lawerne Monmouthshire Wales
Matilda Ruck Servant 18 1873 Female Rockfield Monmouthshire Wales

Struggling to find the family in later census' !!?, altho are mentioned in the
Kelly's Directory of Monmouthshire,1901, for LLANVIHANGEL-YSTERN-LLEWERN
http://freepages.genealogy.rootsweb.ancestry.com/~familyalbum/kangtern.htm

The pilot would have been Frank Henry Joynes from Cannop, born about 1894. He married on 21 June 1916, Mary Isabel Brown, daughter of Amos William Brown, at Coleford. The marriage is in the parish records on this site.
He was gazetted 2nd Lt. in the Royal Flying Corps on 7 February 1918. https://www.thegazette.co.uk/London/issue/30526/supplement/2044
He was transferred to the R.A.F. unemployed list on 17 April 1919.
https://www.thegazette.co.uk/London/issue/31489/page/9963
His service record is on findmypast. His address in this record was Prosper Villa, Coalway Lane End, Coleford.